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: Engine won't fire without ether and runs bad until it warms up.

Hi there. There could be a lot of carbon build up inside the combustion chamber making the fuel not burn properly due to the valves and rings not sealing. First check the spark plugs and see if there is excessive...

Q: My car has been jerking and wont accelerate.

Hello there, thank you for asking about your 2004 Suzuki Forenza. You have a few different faults going on with your car. If you have a 1+2 shift malfunction there are a few potential causes. The most common cause is...

Q: Fast idle - 1983 Mercedes Benz 380SL

Hello. There could be a problem with the throttle cable sticking, causing the high idle. There also could be a problem with the throttle position sensor malfunctioning, causing a high idle. Sometimes a dirty throttle body can cause this problem...

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...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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...