Skip the auto shop - Our mechanics make house calls

Q: Car idles fine for a while then tries to die

asked by on

My car will idle fine then when it sits for a little while it will try to die then picks it's idle back up it will even do it while in drive it especially does it when at a stop light

My car has 180000 miles.
My car has an automatic transmission.

Hi There! It sounds like you may have a dirty or failing idle air control valve causing your engine idle to fluctuate and eventually stall. The idle air control valve is a small valve on the engine’s intake system that reads the air intake as it comes into the motor. This is controlled by the car’s ECM which uses this information to make adjustments to the air/fuel ratio depending on various inputs such as outside air temperature, intake air temperature, load and various other things. As you accelerate, your car’s engine is receiving a much higher dose of fuel than when at idle and conversely, when you let off the gas pedal, there is a sudden change in this fuel supply as a result of your foot letting off the pedal. When this happens, the job of the idle air control valve is to bring this deceleration down to a slow and smooth idle rather than suddenly cutting off the fuel supply causing the motor to die. When the idle air control valve is not working properly, this cause a disruption in this process resulting in the engine not being able to idle properly. I would recommend having a professional come to your location to diagnose and inspect your vehicle.

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

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: When letting off the accelerator, the vehicle will jerk (it feels like a slight back and forth movement)

Hello. I think what we are looking for here are possible problems caused by a "torque-reversal" in the drivetrain. That is, when accelerating or maintaining road speed, the engine/transmission and all the drive links (driveshafts, differentials, transfer case, etc.) have...

Q: No hot air coming from heater

You may have a clogged heater core that may be prohibiting the outer linings of the heater core to get hot. As you know, the heater core is a series of tubes that the coolant runs through that generates the...

Q: truck will not crank or turn over. smoke coming from blower motor under the hood also from ac relay under the hood.

When this occurs, it is a sign that the positive side of an electrical circuit has shorted to ground. In the industry, we humorously call this, "letting the smoke out." This situation creates a lot of heat and has a...

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...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
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.