Why does my car sometimes idle high with the clutch engaged but return to normal when vehicle comes to a stop?

Most engines have a device of some sort to bump up the idle speed when A/C is on. As you don't tell us what you are working on hard to say what yours has for this purpose.

Engines rarely idle at the same rpm all the time. Its normal for changes to occur, especially small ones. Too many variables that can effect such a small change to list. Its no an issue to worry about.

013 Idle Speed Problems PCM Test

007 Idle Speed Problems Scan Data for Idle

test don't guess .

Knowing make model and year would help. Most newer vehicles, 2000 and newer, will adjust the idle control up to compensate for the compressor engaging. Possible there is an issue in the idle air control valve or electrical circuit.

It can be issue with IAC( idle air control valve) causing the problem.

There are many other possibilities causing these idle issues. Engine idles rough.

There are few help links with solutions to troubleshoot such idle issues.

I suggest you refer the link below and follow its troubleshooting details:------

Click the link below:-----

Ford Expedition IAC valve replacing

http://technoanswers.blogspot.com/2012/12/ford-expedition-iac-valve-replacing.html

Bad miss at idle?

http://technoanswers.blogspot.com/2012/01/bad-miss-at-idle.html

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Stumbling and stalling at idle after engine rebuild?

http://schematicsdiagram.blogspot.in/2012/03/stumbling-and-stalling-at-idle-after.html

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1999 Ford F-150 Idles rough and quits when gas pedal is pressed less?

http://technoanswers.blogspot.in/2012/01/1999-ford-f-150-idles-rough-and-quits.html

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Engine stumbles coming off idle when warm?

http://repairhelpcenter.blogspot.com/2012/01/engine-stumbles-coming-off-idle-when.html

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Erratic idle on car?

http://schematicsdiagram.blogspot.com/2011/12/erratic-idle-on-car.html

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Cold start problem and vehicle shudder around 2500 to 3500 rpms

http://repairhelpcenter.blogspot.com/2012/10/cold-start-problem-and-vehicle-shudder.html

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Low idle when cold out side?

http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html

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GMC Sonoma Stalls and idles low

http://technoanswers.blogspot.com/2012/10/gmc-sonoma-stalls-and-idles-low.html

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GMC Idle Air Control (IAC) Valve Replacing?

http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.html

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1996 Camry intermittent engine failure while idle?

http://repairhelpcenter.blogspot.com/2011/10/1996-camry-intermittent-engine-failure.html

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Engine quits at idle?

http://repairhelpcenter.blogspot.com/2011/10/engine-quits-at-idle.html

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Car overheats and Air blows hot at idle?

http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html

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High Idle Problem

http://repairhelpcenter.blogspot.com/2012/10/high-idle-problem.html

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While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

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Idle flair is noticed on car? Rough idle? car will not idle? Erratic idle speed?

http://technoanswers.blogspot.in/2012/02/idle-flair-is-noticed-on-car-rough-idle.html

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High rpm in neutral? Inconsistant high RPM in neutral?

http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html

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Vehicle stumbling at idle and shows code 54?

http://schematicsdiagram.blogspot.in/2012/03/vehicle-stumbling-at-idle-and-shows.html

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Rough idle, staling and Erratic shifting?

http://technoanswers.blogspot.in/2012/03/rough-idlestaling-and-erratic-shifting.html

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While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

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These details will help.

Thanks.

Code 37 is torque converter clutch solenoid failure. Transmission wont shift in and out of overdrive.

Idle is normally set a bit higher anyway for a cold engine. If the warm idle is OK when the clutch is not engaged and gearbox in neutral, then it points to some kind of severe friction in the area of the clutch throw-out bearing, which may be seizing up, or the clutch pressure plate fingers, one of which may be broken off. If the idle is the same, then that simply needs adjusting.


Is there any odd noise when the clutch is depressed, like a low growl? That will be the bearing. You could have someone listen next to the clutch bell housing while you work the clutch pedal, to try to localise it.

Is your truck of the vintage that will be able to start in gear (1st) with the clutch in? If so, then try that and then lift the clutch to see where it engages. If it engages at the very bottom, and the rest is play, then clearly you have an adjustment issue. If the clutch catches at near normal like on inch+ off top end pedal, then you may have a high idle issue together with bag syncs. Where does it feel like it engages when the engine is off? Does it feel normal with only the top end play light, or does it feel light throughout the pedal?

I just replaced my 2004 durango fan clutch and the new fan clutch will not disengage. The fan keeps runnning very loud i have replaced the new one already still doing the samething. Do i have a bad clutch or do i need to have the vehicle idle looked at

Sounds like IAC valve or idle air control valve, usually not very much, maybe $20 - $25, and are usually fairly easy to get to on top of engine on intake manifold. Good luck.