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.

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!
  1. Home
  2. Questions
  3. Check engine light and car idles low/runs differently

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: Car idles and then dies

Hi, A problem like this can be caused by many things. Anything ranging from a vacuum leak, to a problem with one of the engine's sensors. As the nature of this problem can vary widely, I would recommend having a...

Q: Car idling high in park

At such a high idle speed, a large vacuum leak would be possible if the engine didn't return to a normal level after warming up. The idle air control valve regulates engine speed when the throttle plate is closed, allowing...

Q: Problems starting car

Hello. It sounds like the key or the ignition switch could be having contact issues. There are contacts inside the ignition switch. To eliminate a worn key resistor, try another key and see if you have the same result. If...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.