Q: Q: Engine idle fluctuates

asked by on

My car feels like it doesn't want to take off while completely stopped at a light but when I'm driving it's fine.

My car has 88600 miles.
My car has an automatic transmission.

You may have 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. 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: Backfiring and sluggish

It sounds like you may have a misfire or a timing problem causing the motor to backfire. Engine misfires can be caused by many different problems and are generally caused by either a spark or fuel issue or in some...

Q: Multiple problems on a 1996 Jeep Grand Cherokee

Hi there. From the description you have provided, there are multiple problems going on with your vehicle, so the faults may or may not be related. Although the car is showing many symptoms, this may not be terminal. It could...

Q: Why does my shifter get stuck in park in my 2013 Kia Forte

Though this can happen for quite a few different reasons. Most of the time the issue is caused by the brake light switch so I always check to see if the brake lights are working when the issue comes up....

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...
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...
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...