Q: Very rough idle goes away at speed. Can it be the cam solenoid?

asked by on

I have a 2002 trailblazer with 115k miles.one day the car started running really rough at low idle and shakes bad,seems to run smoothly at higher revs...wondering what it could be

Hey there. This may be related to a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer which 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. This is all controlled by the idle air control valve. This can also be caused by other things as well such as low fuel pressure or dirty or leaking fuel injectors causing an over fueling situation. I would recommend having an expert from YourMechanic come to your location to verify the cause of the rough idle and replace the idle control valve if faulty.

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. Very rough idle goes away at speed. Can it be the cam solenoid?

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: Changed battery, now the engine "chugs" at idle and while accelerating

If you disconnected or connected the battery with the key on or any accessory activated then you may have damaged the computer of the car. Firstly, have the Check Engine Light scanned to see what code is stored in memory....

Q: Q: Hello there.

Hello, thank you for writing in. There are several reasons why the vehicle would hesitate to downshift. The first thing you want to do is make sure the engine is well maintained. Make sure you have a clean fuel filter...

Q: Q: Car running and idling rough

This is a common problem on this engine. When you get symptoms such as this with this code it is caused by an issue with the variable valve timing. Most of the time it is because the timing actuator has...

Related articles

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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.