Q: Q: Engine idle fluctuates

asked by on

at the red light and it cut off.

This may be a result of 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. Since this valve is controlled by the vehicle’s computer, it 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 with the help of the idle air control valve making the transition from a higher RPM back down to idle speed. When the engine RPM drops below the normal range of about ~800 RPM, 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?
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. Q: Engine idle fluctuates

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: 2003 Nissan Maxima front driver power seat is not moving forward or backwards. The seat still reclines and moves up and down.

Hi there. The motor or switch on the seat has lost power. First check the fuses and see if any of them are blown. If the fuses are good, then check the switch and see if there is power to...

Q: Vdc light slip light wants to stall when push the gas

The near stalling when you push the gas pedal is a consequence of the air fuel ratio being off as the throttle admits more air to the intake. The causes of the "wrong" ratio lie somewhere in the fuel delivery...

Q: car surges when idle or in park. rpm bounce. car has cut off, but cuts back on.

It sounds like your idle air control valve could be failing. The idle air control valve is responsible for maintaining the proper amount of air into the intake while the vehicle is slowing down to a stop and resuming idle...

Related articles

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...
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.