Skip the auto shop - Our mechanics make house calls

Q: Check engine light and car idles low/runs differently

asked by on

Check engine came on, hesitated to start and when accelerating car hesitates to push while driving. Also idles low. Had full maintenance about a year and a few month ago including spark plugs etc a complete tune up, spent nearly $2k in repair. What could be the problem?

My car has 153000 miles.
My car has a manual transmission.

A: This may be related to a dirty or failing i...

This may be related to a dirty or failing idle air control valve. The idle air control valve reads the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. 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. When the engine RPM drops below the normal idling range of 750-800 RPM (for most cars), this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and repair your idle air control valve.

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・Save up to 30%

Get a quote

What others are asking

Q: My Jeep starts for a couple of minutes but it wont stay running.

Hi there. If the engine is trying to start up and not staying on then the fuel could be jelled up in the fuel tank at the temperatures outside if there is excessive water in the fuel. I recommend putting...

Q: Car not idling smoothly

This is typically caused by a carburetor problem. Most of the time it is as simple as an adjustment of the mixture. This is something that must only be done by someone with carburetor experience. If you need to have...

Q: Cannot shift out of park

There are several components to the shift inter-lock system that can prevent the shifter from moving properly. If the brake light switch is not sending the proper signal to the inter-lock mechanism, it may not release the shifter. Also, if...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
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...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...