Q: Car is idling low at less than 1 RPM at a stop

asked by on

When the car is at a stop light it idles at less rhan 1 rpm when it is is in drive (in neutral it doesn't do this) The car has an automatic transmission. It makes a loud hum and shakes when it does this. What might be the problem? More importantly what might be a solution? Thanks

My car has 120000 miles.
My car has an automatic transmission.

Hi there. This may be a sign of a failing idle air control valve. The idle air control valve 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 failing, your vehicle will stall instead of slowing to an idle after the release of the throttle. If you would like to have to have this done, a qualified professional, like one from YourMechanic can come to your car’s location to replace your idle control valve.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Car is idling low at less than 1 RPM at a stop

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: Check engine light is on. I dont know what to do about it.

In order to have your check engine light is on checked you should have YourMechanic or another mechanic do a check engine light inspection. This inspection will scan the computer and retrieve any stored codes in memory. The codes received...

Q: my car jerks and seems like it wants to shut down when im at a red light and i roll the windows up lights seem to dim out

This sounds like it could be two separate problems. You may have been on the right track with the battery, but if the voltage drops while the engine is running, that sounds more like a charging system problem. It might...

Q: Replaced master cylinder, bled all four sides pedal still goes to floor HELP 😔

If you have clean brake fluid at the wheels after following the proper bleed sequence, I would try bench bleeding the master cylinder one more time and bleeding at the wheels afterwards. If you still don't have a proper brake...

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...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.