Skip the auto shop - Our mechanics make house calls

Q: Car jerking when slowing down

asked by on

My car sometimes jerks while I'm driving it feels like it's about to die on me. It mostly does it when I'm slowing down. I just got my spark plugs replaced thinking that would solve the problem. But it's still happening.
My car has an automatic transmission.

A: This is a common symptom of a dirty or fail...

This is a common symptom of a dirty or failing idle air control valve. As you know, 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. As 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 (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!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: After I replaced my center bearing, a knocking sound from under the truck had occurred, and it has been slowly getting worse.

Hi, thanks for writing in. It sounds like you have a drive shaft or a half shaft issue. When you get under your car, try moving the axle back and forth. Any play could potentially be your sound. If you...

Q: Rough idle and engine stalls out.

This suggests a rich fuel condition as evidenced by the black fouled out spark plugs. This can happen for a couple of reasons such as faulty or leaking fuel injectors, or a faulty or dirty idle air control valve. ...

Q: Car shaking

Unfortunately there are many different reasons that could cause your Honda Civic to shake. These reasons include a lack of adequate fuel pressure, faulty spark plugs or ignition coils, or even weak or broken engine mounts could all cause that...

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...
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...