Skip the auto shop - Our mechanics make house calls

Q: RPM revs too high

asked by on

My car has a problem with the rpm. When in idle it revs to about 2000 rpm and that's when the compressor kicks out. When the compressor kicks in it goes down back to 1200 rpm which is really high.

My car has 188000 miles.
My car has an automatic transmission.

Hi, thanks for writing in. This is a sign of a failing idle air control valve. This is a unit that is located on or near your intake manifold that monitors the air intake as it is mixed with fuel prior to being injected into the engine. This valve is controlled by the vehicle’s computer which will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed. However, when the engine RPM drops below the normal range of 800 RPM (for most cars), it is more than likely that you are dealing with an IAC valve problem. In cases where this valve is clogged or is nearing its replacement age, your vehicle will stall instead of idling after the release of the throttle. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this rough idling issue for you, and make or suggest any repairs as needed.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: How do I fix my noisy and vibrating Abs module?

Hello there, the ABS module is an important safety feature on your 2008 Toyota Corolla. If the ABS module is failing and it has been diagnosed to be faulty then it should be replaced. There are further tests than just...

Q: Why do my car shut off when I stop

The first and easiest thing to do is to check for air leaks. Any air that gets into the engine without going through the air mass meter will lean out the fuel mixture and affect the idle. Inspect the rubber...

Q: Shaking and stalling during low idling

There are no common issues that would cause this problem - especially with the relatively low mileage. I recommend testing the computer for codes causing the stalling you have. If the computer sees the stall, it should set a code...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...