Skip the auto shop - Our mechanics make house calls

Q: High idling happening occasionally after driving over 8 miles

asked by on

My car sometimes idles high. It happens suddenly and last usually until I restart the car. Then, several weeks could pass without any issue only to randomly appear again. The mileage is 150,000. When it happens, the car would go very fast without the acceleration on my part. The same thing is with reversing. It would go so fast that I would have to apply brakes. The engine would get noisy as I stop the car in park. This accelerating occurs usually after the car is in motion for over eight miles. Also, there is no check engine light. I took the car to the shop and they couldn't find anything wrong. The issue still occurs occasionally. What should I do?

Hi there. Most of the time this is caused by a problem with the throttle body. I usually clean it out first and inspect it for wear. If there is wear around the throttle plate then it needs to be replaced. If not the cleaning may take care of it. If it doesn’t then I test the idle control valve and the throttle position sensor as both of these will cause this. If those are also fine then it may be a sticking EGR valve but that is not as common. If you want to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to inspect your high engine idle.

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: Car likes to make a chugging noise when accelerating up a steep hill. It usually happens around 55 mph.

Hi there: In many cases, when your Malibu begins to struggle when you're climbing a hill it's more of an indicator of fuel system issues; such as a clogged fuel injector nozzle or dirty throttle body. It could also be...

Q: Laboured idling and backfires

This has all the symptoms of a fuel supply issue. Such an issue can cause a lean fuel mixture and backfiring - either from low fuel pressure or inadequate fuel volume. Make sure the fuel pump relay doesn't have a...

Q: Hi I rebuilt my tranny works fine when on a jack but no movement when all wheels on the ground. Why is that?

Hi there. When the wheels are in the air, they are essentially free-wheeling, so issues like low transmission fluid or pressure would not be discovered until trying to test drive the vehicle while under load. This is likely what is...

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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
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.