What Causes Rough Idle And Hesitation

Changed both o2 sensors ( I had a check engine light) 2. on highway, going at constant speed it fares pretty ok;. I dont know if this is the cause or the effect of the rough and lowered idle, but I decided to check the timing while the car warmed up from full cold, and after that first minute when the idel suddenly dropped, timing retarded from 20* to about 12-14 degrees and gets kinda erratic, then goes back up to 20* when the idle smooths out. Once Im up at cruising speed and I dont have to press the gas much it runs fairly smooth. Misfiring could be an issue with bad HLA's, timing belt, or something like that. Then today my SES light came on while sitting in traffic, stopped. A malfunctioning or inoperative Manifold Absolute Pressure Sensor can cause drivability symptoms such as hard starting, stalling, harsh or poor transmission shift points, rough idle and hesitation. First round of efforts will be the easy typical things- Clean throttle body / mass air flow, Seafoam in the fuel. Just picked up a '06 with +190K miles and first thing I noticed was a rough idle. A crank sensor will cause random stalls, slow engine starts, mis fire, and complete no start symtoms if it is totally fcked. Complaint #3 - MY FUEL INJECTED CAR IDLES ROUGH AND STALLS AT STOP SIGNS Stalling at stop signs while the vehicle is in gear on carbureted vehicles could be caused by a failing Idle Speed Control Motor. Rough idle and slight hesitation on acceleration can be attributed to a clogged EGR system and/or other emissions related components including a faulty or dying O2 sensor, clogged catalytic converter, exhaust leak, etc. And yes, I did exhaustive searches in these forums on this topic. Re: rough idle and hesitation? the spark plugs could come into play because the NGKs are generally a better plug, so they may have been getting a more complete combustion, leading to the O2 seeing less oxygen, leading to a different duty cycle on the injector. The coil and injector are a long shot if it actually runs alright but acts up at idle. ) generally don't sound sweet at idle. My 2000 Ford Expedition with the 5. CEL that comes and goes. Steps I have taken: Sent it to the dealer for a walnut blast of the intake valves. Misfiring could be an issue with bad HLA's, timing belt, or something like that. This has eliminated about 80% of the problem, but after driving around for a while I realized that the problem is still there, just at a greatly reduced intensity, including both the hesitation and the rough idle. flash forward to this weekend. These conditions can cause a rough idle, as well as many other engine problems. Do our trucks have an idle air sensor? Your local autoparts store should be able to read the codes for you. Blast off the big junk with compressed air (gently) and then soak in white vinegar for several hours. Q: What causes engine knocking?. Ignition control module. CarComplaints. Also can feel a hesitation under light to medium acceleration. Worse problem is bad hesitation when accelerating after throttle at idle position, sometimes stalling. seems a little better at running temp. - Very rough idle, especially before it warms up, this causes a light bucking while in drive with the foot on the brake. And just browsing the first 15 pages of this thread, "rough idle" has different meaning to each driver. When I turn the AC off, it runs. It’s likely you’ve experienced a rough idling vehicle – which just means the car feels rough and bouncy when the engine is running. (Please see our articles on tuning One-Screw Carburetors and Two-Screw Carburetors. It could also be a TPS sensor (Throttle Position Sensor) so be sure to check your computer codes to be sure. But slight load and cruising start to jerk and misfire. anybody know what causes the 3. I let off the throttle and then shifted back into D and let it idle. Does anyone know what could be the cause of my hesitation and rough idle issues?. Then I noticed the idle becoming a little bit rough at times and gas mileage reducing from about 16 mpg to about 11mpg without any change in driving habits. almost like an old carb loading up with fuel. Engine 19-Nov-2015 404000 Fuel System Concerns Issue: Symptom : Engine MIL illuminated on IPC. These conditions can cause a rough idle, as well as many other engine problems. The problem needs to be approached first with a thorough understand of how to troubleshoot the cause or causes BEFORE you throw parts at the problem. i got the navi used like 6 months ago. Many things can cause an engine to lose power: bad timing, airflow obstructions going into or out of the engine, carbon buildup on spark plugs, bad gasoline and improper fuel burn in the cylinders are just a few. 2nd car I drove after this ended up having a rusted fuel tank. Rough idling sometimes. Idle is most rough, when the engine is first started in the a. Brought it to the dealership this morning (under CPO). Rough idle, pinging, hesitation, stalling, etc. sounds like you have covered most of the obvious issues that cause rough idle. I am trying to tune out a hesitation in the off idle part throttle range. It makes no difference whether the engine is hot or cold. MAKE SURE THAT THE IDLE MIXTURE SCREWS ARE PROPERLY ADJUSTED. A rough idle may be caused by a faulty ignition coil, a vacuum leak, or an ignition system problem. But it didn't solve the problem. I notice you say that the problem happens when it is warm, is it only when it gets warm or is it present cold?. This will cause a phenomena called "puddling" where little droplets of gasoline adhere to the intake manifold runners. The most likely causes here would be:. A misfire will cause the engine to momentarily stumble, or lose rpms, and then regain its normal engine speed. My motor was replaced in august so i would assume if the mounts were shot the shop would have said something but i will look into the motor mounts. I also would occasional notice it difficult to smoothly start moving off from a stop because of a slight engine hesitation and found myself giving it more gas that usual to start off the. The hesitation and rough idling appear to be getting worse (I drove it this morning and afternoon), but the check engine light isn't coming on. I recently dropped a new 260 long block into my 64. Unfortunately, none have been able to solve the problem. When driving it I can feel the engine miss like a plug is bad throughout all gears around 1500-2000 and 3000RPM as well. Said that's a sign of a bad fuel pump. Incorrect idle speed setting. There are several reasons why this happens - some major and some minor. I've changed out the fuel pump, catalytic converter, O2 sensors, TPS, swapped out he MAF with another, spark plugs wires and coil and can't seem to find a solution at all. rough idle and hesitation once engines is hot, no codes on DIC. My idle is around 600-700,I have all the stuff to do mhd but i will raise the idle as a last resort. I spent a large amount of money on all these sensors and sh#t to get my BUTT KICKED by a 4$ PCV valve!!!!! CHECK YOUR PCV VALVE FIRST!!! Truck runs great cold/warm no rough idle,no hesitation, and no blue smoke easier on oil and gas!! hope it works for you!. My mind went straight there too. lately when the truck sits idling whether in the drive way, street, anywhere, i've noticed the truck idles rough, smooths out and idles rough again. 4L seems fine at the 60k mile mark. Changed both o2 sensors ( I had a check engine light) 2. The EGR valve was faulty so I replaced it. Rough idle and hesitation sounded like a vacuum problem, so I checked the TBI. This is not something you want to avoid fixing for too long or it will cause more headaches and expenses. Cleaned out the Idle Control Valve. Could've been due to the bitter cold we're getting in the midwest, but what else could cause this issue?. This caused stalling, and hiccups at idle and also under load at highway speed. I am surprized that you dont get a P0300 for the rough idle. The 1994 Cadillac DeVille has 1 problems reported for backfiring hesitation and rough idle. Hi, after van has ran for awhile when you come to a stop the idle is really rough. Hi, I am having a problem with my chevy 350 engine that I just installed back in August. It doesn't normaly do it when the car is warmed up but has a few times when the car is warm. It's really annoying because at a stop light, you go to move and it does the bucking bronco for a sec when you come off the line. Complaint #3 - MY FUEL INJECTED CAR IDLES ROUGH AND STALLS AT STOP SIGNS Stalling at stop signs while the vehicle is in gear on carbureted vehicles could be caused by a failing Idle Speed Control Motor. This made the idle pretty smooth. When its just sitting in park at an idle it feels like it's got a slight hesitation can a o2 sensor cause it to do that Yes, an o2 sensor not properly reading could cause a rough idle. Solution: The first step is to remove your spark plugs and take a good look at them. Hard Starting/Hesitation/Rough Idle + More issue resloved also tech bulltein! First off this is mostly for other GM's DO NOT DO THIS TO ANY LSJ OR LNF, Your fuel injectors must be replaced to fix this issue(if fully clogged) this will however help you determine if this problem apply s to you. 2000 GM sierra, 5. got to work, noticed that mpgs had dropped by over 3 in just the. It could be a couple other things, too, but those are the most common and first things you should explore. By Mark Giammalvo. Rough idle, hesitation and loss of power in low/lower RPM's - PD BEW VW MKIV-A4 TDIs (VE and PD) Rough idle, hesitation and loss of power in low/lower RPM's - PD BEW - TDIClub Forums www. Hesitation, jerking and rough idle. Under engine electronics, Check Measured data blocks 00, 07 and 99. 4) Venting system failure. It appears as a really rough idle only when stopped and in gear (it's present when idling, but much less so). rough idle / hesitation. I think it may be ignition, timing, or carburetor related. As you go up in elevation, the air becomes less dense. I took my car to the shop, and this is what was done. If you live in a state with vehicle emissions testing, this may be the reason why your car fails the test. Rough idle, hesitation when I hit the gas and after it warms up trouble going up hill. Some hesitation on acceleration. Spark plug/spark plug wires. Worse problem is bad hesitation when accelerating after throttle at idle position, sometimes stalling. The aluminum intake might have also warped due to heat, incorrect tightening sequence or variation of torque settings, all which might also cause a leak. There are several reasons why this happens - some major and some minor. Well I did that and this has never done this before but now I'm having a big misfire and its getting worse while it runs. When its just sitting in park at an idle it feels like it's got a slight hesitation can a o2 sensor cause it to do that Yes, an o2 sensor not properly reading could cause a rough idle. Rough Engine Idle Proper engine combustion is crucial for maximizing engine performance. And then she ran fine. This is caused by the less-than-optimum engine combustion firings that result in poor engine performance. IAC as mentioned above also, will cause rough idle and fluctuating rpm's when in park. 7L is an odd fire v-6 and when the odd cylinder fires it causes vibration (rough idle) i don't know if any of the above are true?. My only problem is a rough idle when i pull up to a stop sign /light. There's very noticeable hesitation while accelerating and cruising. It only takes a minor problem like a fouled spark plug to cause your engine to vibrate. im sure it is a normal problem for all fords. Once engine gets warmed up it goes away and runs great the. CarComplaints. I have a friend who has a 2006 Mazda Tribute 4 cylinder. My car is rwd so that cant be it. A few days later it began to stumble and hesitate upon acceleration. the motorcraft ones are 70 bucks. I'm at a loss. We start to accelerate and the car moves, then there's a hesitation in the acceleration. It can also cause the Check Engine Light (CEL), Service Engine Soon (SES) or Malfunction Indicator Lamp (MIL) to illuminate and can set a trouble. Hi, after van has ran for awhile when you come to a stop the idle is really rough. rough idle / hesitation. 2 rough idle and slight hesitation on pick up JZM have looked at this a few times, but to no avail. 2) Fix cause of flooding. i noticed that there is now hesitation while drivinf and a very slight rough idle in park or at the light. I agree that throwing money at the engine is not a good way to solve problems, however At 184,000 miles you have a lot of possible areas to consider that may be contributing to this. Can this actually be the cause. And yes, I did exhaustive searches in these forums on this topic. I checked everything from plugs, coils, vanos, and even the engine mounts; all in good shape. 4L seems fine at the 60k mile mark. The best course of action is to take your vehicle to an Omaha auto service professional, but here are a few things it could be…. The symptoms are almost exactly the same (misfire codes, rough idle, hesitation, loss of power), though it hasn't stalled and I'm also noticing a gnarly smell that's presumably the result of unburnt fuel. I then put it in P and gave part throttle to get the RPM's up to 3000 - no audible misfires, backfires or sputtering. I feel it when i stop & go. Idle was always 650 and was never above or below by more than 100. Rough idle and slight hesitation on acceleration can be attributed to a clogged EGR system and/or other emissions related components including a faulty or dying O2 sensor, clogged catalytic converter, exhaust leak, etc. It does it regardless to whether the AC is on or off, and doesn't do I at every cold start. With the new carbs, it idles poorly and has a major hesitation on acceleration from idle. Rough idling and hesitation can be caused by several different things. The air/fuel ratio can also be affected by changes in altitude. Engine Troubleshooting. If it just unseat with idle vacuum, try and adjust pintle height if equipped. Here is a view if the Buick's ECM being back probed after being taken down from its hiding place behind the dash. A bad oxygen sensor may misread or misinterpret an engine's air/fuel mixture or air/fuel requirements and cause too little or too much air and/or. I checked everything from plugs, coils, vanos, and even the engine mounts; all in good shape. once engine is hot, the shaky, rough idle doesn't seem to be as evident. I bought myself a VAG-COM cable off eBay and an using the Ross-Tech software to read the codes and gather data. Re: Rough Idle, Hesitation, Random Codes, HELP Jun 29 2015, 4:35pm Pulled the plugged off the coil while it was running and got a strong arc on everything but #1, when I pulled the plug it looked good. My mind went straight there too. It only takes a minor problem like a fouled spark plug to cause your engine to vibrate. Then take off the 2 8mm bolts off the plate on the back of the FITV. 8T 4Motion that is experiencing an intermittent hesitation when at speed and occasional rough idle. when idling engine would sputter every few seconds;. rough idle and stalling. When it warms up the idle is rough. It idles very rough no matter the temp and the exhaust sputters and lightly pops. I let it keep idling like this (RPM's about 500). If the fuel mixture becomes too lean, "lean misfire" may occur as the load on the engine increases. The problem needs to be approached first with a thorough understand of how to troubleshoot the cause or causes BEFORE you throw parts at the problem. Rough idle is different than hesitation. Engine rough idle problems arise because car engines are demanding. Cam sensors are €50 Euro each. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits. A relatively small leak can cause big problems. i noticed that there is now hesitation while drivinf and a very slight rough idle in park or at the light. This type of reading is a strong indication of a serious engine problem. rough idle and hesitation once engines is hot, no codes on DIC. Rough idle and sometimes would experience intermitant hesitation at ignition and at acceleration. My idle was so bad it started dieing on its own. Fuel consumption will be affected as well. Reassemble the system, hook your EGR valve back up and take your car out for a ride. Some hesitation on acceleration. My 73 Mercury Montego with the 351w started over heating on idle after I got it back from a shop since the carb was out of tune and was making it run like garbage. If it idles fast, step on the throttle and slip your toe off the pedal to let it snap up quickly. During idle it would sound as if it were about to shut off but it wouldn't. What can cause a misfire and rough idle and hesitation on 1979 Chevrolet C10 350 truck? I have piston o-rings leaking oil so I clean my spark plugs one at a time every once a month it gunks up. I've replaced all of the main things that cause rough idle and have yet to perform a Leak down or compression test. This causes a TON of people’s hunting idle problems (it’s a source of a vacuum leak). I Have A 98 5. Rough Idle + Rotten Egg Smell + Check Engine Light. hello all i am new to this site, i looked and searched for a answer to this. Defective/clogged fuel pump. That's my I'm asking. Rough idle and sometimes shake, rough idles are misfire, what needs to be check are sparkplugs and sparkplug wires, There is a possibility the ignition coil is problem, If the vehicle stumbles on acceleration the ignition coil should be tested ,a replacement may be required for the solution to the shudder. Any throttle causes a shot of fuel from the accel pump so it seems to work and changing which hole the linkage is in also causes a bad hesitation (outer hole), so something is causing the accel pump. Older engine's are equipped with a distributor ignition system. Rough idle is about the same but hesitation is getting slighlty worst. Rough idle, hesitation and loss of power in low/lower RPM’s – PD BEW VW MKIV-A4 TDIs (VE and PD) Rough idle, hesitation and loss of power in low/lower RPM’s – PD BEW - TDIClub Forums www. ISSUE: A rough idle, hesitation on acceleration, and/or a stall after start-Up with no DTC's present may occur on some vehicles. correct - thats the valve - and see the hoses as well - check them for leakage and cracks - I don't think you'll get anymore horsepower with the DME /airflow meter swap - HOWEVER you will really notice how much better the car runs - and the later style DME box is easier to chip , so with the chip you will feel a LITTLE more. Thanks for the intell. But the cooling system besides the water pump is all new but. Plugs, wires, fuel filter, oil filter, air filter, cleaned the throttle body, cleaned the maf, tranny filter. could a knackered diverter valve cause these problems? I suppose with 110k on the original one it wont hurt to change, ive. any suggestions now?. org, is the worlds largest automotive enthusiast group exclusively geared towards the General Motors GM J-car platform including the Chevrolet Cavalier, Pontiac Sunfire, Pontiac Sunbird, Pontiac J 2000, Oldsmobile Firenza, Buick SkyHawk and Cadillac Cimarron. My mind went straight there too. I had similar issues and had the dealer do the latest ECM update and it fixed it. Rough idle and sometimes shake, rough idles are misfire, what needs to be check are sparkplugs and sparkplug wires, There is a possibility the ignition coil is problem, If the vehicle stumbles on acceleration the ignition coil should be tested ,a replacement may be required for the solution to the shudder. The most common causes are; bad spark plugs, bad spark plug wires, and a dirty air filter. I've replaced all of the main things that cause rough idle and have yet to perform a Leak down or compression test. Rough idle 4. I gave fuel treatment and engine restorer, which there is definitely. Spark plugs & wires; fuel filter; air filter; fuel pressure; vacuum issues. Any throttle causes a shot of fuel from the accel pump so it seems to work and changing which hole the linkage is in also causes a bad hesitation (outer hole), so something is causing the accel pump. Engine misfire causes the power to drop and reduces vessel performance. first the basics. But ever since when the truck is not moving and sitting at idle in gear (think red light) the idle gets really rough for 2-3 seconds. anybody know what causes the 3. Setting the idle for the highest vacuum idle reading will result in too little clearance of the throttle plate; forcing too much of the idle mixture through the lower idle port and too little through the idle transfer slot. Vibration when the transmission is loaded but not moving (car in drive, brake on) I performed a Seafoam treatment through the PCV tube at that time. Rough Idle/Engine Hesitation when engine hot was created by 96Pontiac Okay so I looked around on the forums both for the codes I have and my problem my 1996 Pontiac Grand Am (2. This systems can cause hesitation when maladjusted, by using a timing light this situation can be checked and corrected. At idle, the tach fluxuates from about 700 to 1000, and sometimes fells like its going to die at stop lights, it never has actually died though. That has since been fixed but I have noticed since this incident whenever it rains or is humid out the car hesitates and has a rough idle to it, normally only in the morning on the way to work. Below are the top 5 causes of engine hesitation while idle, when cold, or under a heavy load:. I know idle is supposed to be between 1000-1200 but it idles between 800-900 and will drop down to around 500 for a second and then back up to 800-900. Then I noticed the idle becoming a little bit rough at times and gas mileage reducing from about 16 mpg to about 11mpg without any change in driving habits. These may be caused by the injector harness chafing and shorting to ground under the fuel injection control module, along the intake manifold or on heater hose clamps. My 2012 has a hesitation in its acceleration when launching from a complete stop. A faulty throttle position sensor might cause hesitation. Maybe an injector is dirty/clogged. You can unplug something and get a code that doesn't tell anyone that circuit XYZ is unplugged just that, that is the area of the problem to chase down. Common causes of engine stalling and rough idle include a faulty mass airflow sensor, faulty engine coolant temperature switch/sensor (typically at cold start only), worn spark plugs, wires or defective ignition coil(s), inadequate fuel delivery or pressure (clogged fuel filter,. Under engine electronics, Check Measured data blocks 00, 07 and 99. Idle speed would dip down to 500 RPM then cause a good shudder. The coil and injector are a long shot if it actually runs alright but acts up at idle. When it goes bad it will think the throttle plate is either to closed or to open when in reality it's fine. It is one of those problems that is bad enough to notice and bother you, but not quite bad enough to put a lot of time and money into fixing. Hope I can get to get some help with a problem I've been trying to work through for a couple months now. Excursion - King of SUVs - Exhaust leak cause rough idle? - Towing TT yesterday and halfway to destination started getting a shudder in the lower RPMs. quik edit1: notice something else you said, well you said -- "why do you set the computer into diag mode, set the timing and idle rpm speed," the answer is: that is the correct procedure for setting the base idle and the timing for, at least, the OBD-I ECU. Xterra: My 2001 Xterra started to idle and run rough with hesitation My 2001 Xterra started to idle and run rough with hesitation and a loss of power during drive cycles intermediately. 2001 V70XC, 155kmi Have very rough idle + misses and hesitation when accelerating (>3000rpm). It can also cause the Check Engine Light (CEL), Service Engine Soon (SES) or Malfunction Indicator Lamp (MIL) to illuminate and can set a trouble. Hello, I have a 2006 2. Often, the most difficult part is to determine exactly what is causing the issue. There's very noticeable hesitation while accelerating and cruising. Any leak in a fuel system's vacuum will intermittently throw off the air/fuel mixture that enters the engines combustion chamber. With the engine running, the battery terminals should be at 14. Re: rough idle and hesitation? the spark plugs could come into play because the NGKs are generally a better plug, so they may have been getting a more complete combustion, leading to the O2 seeing less oxygen, leading to a different duty cycle on the injector. Although I haven't specifically used a scanner to read the actual idle speed of cold vs. Re: 2005 Type-S rough idle + hesitation under load Mmkay, 'Diagnosis' at the local dealer cost £50 and revealed the fault code to be P0171 - Fuel metering too lean with a probable cause of No. Most hesitation can be attributed to leaks or something like poor fuel delivery. Engine hesitation and rough idle. This in turn may cause a momentary misfire of cylinder #3 until the fuel vapor is cleared of injector #3. I have been battling this for a few months now. I also would occasional notice it difficult to smoothly start moving off from a stop because of a slight engine hesitation and found myself giving it more gas that usual to start off the 'line'. It has recently devoloped a low and rough idle. I changed the spark plugs, and the spark plug wires. This changes your base idle speed (TPS disconnected) and can also cause a rough and wandering idle as well as possibly causing your car to stall when you push in the clutch. Rough idle is different than hesitation. Just removed throttle and replaced bad TPS and also did the o2 sensors, codes cleared, but van still has terrible hesitation and lurches when I try to accelerate and doesn't sustain a good idle, but only when engine is cold now , after sitting all night. It’s likely you’ve experienced a rough idling vehicle – which just means the car feels rough and bouncy when the engine is running. And when the EGR valve gets stuck open, it'll cause a rough idle condition that may hard to diagnose. Ok idle is fixed cause apparently im a knucklehead and i was thinking tighten the idle mixture to lean it out. When the DPFE sensor is failing or goes bad, it causes rough idling, a reduce in power, and it may cause the "check engine" light to come on. Components in the fuel, ignition, emission and other systems should work correctly. Top 10 Causes of a Rough Idle 1. It was idling noticeably rough as expected. It's very hesitant to rev and tends to die when pulling in the clutch to stop. But after about one minute the idle starts to accelerate then go down. The best course of action is to take your vehicle to an Omaha auto service professional, but here are a few things it could be…. In addition to a warning light, a bad coil or spark plug can make the engine have a rough idle, misfire or surge. Distributor cap. When cold, I can't get it to fire up with anything less than 3/4 turns on the idle screw, after which it idles high around 1200 rpm. The cam sensor failure will cause over fueling, bad rough running & mis fire but the car should still run but badly. This in turn may cause a momentary misfire of cylinder #3 until the fuel vapor is cleared of injector #3. My 73 Mercury Montego with the 351w started over heating on idle after I got it back from a shop since the carb was out of tune and was making it run like garbage. CarComplaints. Rough idle and hesitation while accelerating started a week ago, has become much worse. 4l) seems to be having, and I couldn't really find any definitive answers. The blinking would stop after a few minutes and the light would go away. rough idle and hesitation once engines is hot, no codes on DIC. Rough idle, low power on acceleration, backfire on acceleration along with black smoke, hesitation Out of the blue the 75 FJ40 started this behavior after starting it up two days ago. That fixed the rough idle and it drove fine for a day or two. 0L engine is also known for excessive tapping noise from the injector rail. I was experiencing a really rough idle/vibration and a little hesitation. 2011 Ecoboost F150 - Rough Idle, Hesitation, Missing, Limp Mode - Fixed Discussion in '2009 - 2014 Ford F150 Truck Forum' started by KentuckyKid, Oct 17, 2015. Really got me worried cause I didn't have the power when. I don't have an egr valve. Hi, I am having a problem with my chevy 350 engine that I just installed back in August. If your older gas engine, starts hard, idles poorly, or accelerates with hesitation the problem may or may not be solved with replacing a part or parts. rough idle and hesitation. I have taken my car to many repair shops. A problem with the engine control module might cause hesitation. But ever since when the truck is not moving and sitting at idle in gear (think red light) the idle gets really rough for 2-3 seconds. doesnt really seem like a backfire, its not loud anywaysit is mainly noticeable in lower gears while i am accelerating. Then I noticed the idle becoming a little bit rough at times and gas mileage reducing from about 16 mpg to about 11mpg without any change in driving habits. A rough idle may include any of the following: Idling below or above its regular speed. Cleaned out the Idle Control Valve. It doesn't normaly do it when the car is warmed up but has a few times when the car is warm. DIAGNOSIS: 1. I have a 2004 Passat 1. Here are some: Stalls at idle, stalls when I put the clutch in, stalls when I turn a corner, misfires, surges, no power, cuts out, no power at top revs, runs rough, etc. well, i changed the spark plugs, wires, fuel filter, used seafoam in booster line, checked for arcing at night from misfire - nothing seen, and i still have a rough idle, slight hesitation, and now my exhaust is popping quite a bit. This hesitation has constantly gotten worse. 4L are very well documented. I was experiencing a really rough idle/vibration and a little hesitation. This won't help wot (amp has wot check valve ), but it will clean up a rough idle with a bad amplifier. since you dumped it that is a sure fire way to solve a vehicles problem. Here is what was done. Parked, came out, and it started fine but would die as soon as I accelerated. When you first start it it will go into severely rough idle and falls on its face if you try to drive it. Idle was always 650 and was never above or below by more than 100. ECT has 60,000 miles on it. Ignition control module. Basically now I start the car when cold and it fires right up, then rpms chug and idles poorly, and puffs some white or greyish smoke for a bit. but i have 99 dodge dakota 4x4 5. The fuel filter was changed a few years ago, and the plug wires around 120k miles. Rough Idle, lost of power and misfires At some point during the month of August the Roadfly forums are going to become archive only. Loose or broken vacuum hose/vacuum leak. Gotta troubleshoot them individually to see if they are related or not. The 2005 Ford Escape has 6 problems reported for rough idle and hesitation on acceleration. This usualy happens on cold mornings or when it's been raining and the car has been sitting over night. Therefore, none of them alone is cause enough to replace one. First round of efforts will be the easy typical things- Clean throttle body / mass air flow, Seafoam in the fuel. Rough idle, hesitation and loss of power in low/lower RPM's - PD BEW VW MKIV-A4 TDIs (VE and PD) Rough idle, hesitation and loss of power in low/lower RPM's - PD BEW - TDIClub Forums www. This can cause lambda control problems, especially at idle and part throttle, leading to rough running,possible rise in fuel consumption too. rough idle / hesitation. I was experiencing a really rough idle/vibration and a little hesitation. re: 1998 f150 4. Does anyone know what could be the cause of my hesitation and rough idle issues?. Re: Root cause of Mercury 2-strokes' rough idle Rough idle is a subjective statement. when it's idling rough, it's not like the trucks going to blow up, just enough for it to be noticed. There's very noticeable hesitation while accelerating and cruising.