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Probably because the compressor is cycling on and off to maintain temperature without freezing. Compressor on car runs slower RPM, compreesor cuts out and RPMs go up.
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The car starts fine but idles up and down then stops running?
Check the air filter, it's probably clogged.
Why would a 1999 Ford Contour shake or vibrate at idle?
I also wish someone would answer this question as my 1997 Ford contour does the same thing. It shakes and vibrates very bad when it idles and it idles really low. They set the idle up to make it so it wouldn't die so now when I start it it revs up really bad then it idles down then it idles down to low and shakes I also wish someone would answer this question as my 1997 Ford contour does the same thing. It shakes and vibrates very bad when it idles and it idles really low. They set the idle up to make it so it wouldn't die so now when I start it it revs up really bad then it idles down then it idles down to low and shakes
Your 87 Nissan truck idles up and down?
check for vaccum leaks.
What is causing the high idle sound when you start your car?
Cars often idle fast when you start them up. The automatic choke will make the car idles fast for a while then the idle speed will slow down, once the engine warms up.
98 Chevy Metro idles up down worst when turn headlights on?
When you turn on the headlights of any car it causes a load (or horsepower drag) on the engine. Your car has an idle problem and the load on the alternator simply exacerbates it.
1987 Toyota Camry ac works until engine spontaneously idles up appx1500 rpm at which time ac compressor still runs but air temp gets warmer New timing belt Car does not idle up without ac on?
Warm air coming from the air conditioner compressor should not have anything to do with the timing belt. You probably need to recharge your air conditioning system.
2002 ford pick up idles fast when first stated then idles low runs good going down the road but when you stop it idles low and rough?
It could be a dirty air filter or a dirty throttle body.
I have an 1992 Oldsmobile 88 It starts and idles good but will die win I drive the the car down the road what do you think is wrong will it?
Could be a plugged fuel filter, time for a good tune up.
Your 1991 Honda idles up an down cold but after car gets real hot it go to nomal?
lol that's what its suppossed to do... if when idling low it stalls or is really roush then you might have a real problem.
Lawn motor idles up and down?
Either the fuel mix is adjusted wrong or the carb is dirty
Why does car heats up when ac is on?
The car seats because of the extra energy it needs for the AC compressor work
Engine idles up and down what is wrong?
It really depends on the make/model of your car. Suspects include: Idle Stepper Motor/control valve, engine CPU, fouled injectors, incorrect spark plugs
