Skip the auto shop - Our mechanics make house calls

Q: My car idles rough when stopped

asked by on

My truck is idleing really rough only when stopped. It wants to die if stopped to long I changed the idle control valve and all 6 coils but it didn't help

My car has 187000 miles.
My car has an automatic transmission.

A: This may be a sign of a leaky injector or p...

This may be a sign of a leaky injector or potentially an incorrect idle air adjustment. A leaky injector can cause a rich fuel condition as it may leak too much fuel into a cylinder not allowing the combustion cycle to burn the fuel evenly resulting in excess unburnt fuel being unused and momentarily flooding the motor causing this kind of rough idle. When this happens, you may notice a bit of black smoke coming from the exhaust as well as a slight fuel smell.

This may also be a slightly misadjusted throttle plate. The throttle plate is adjusted at a specific angle to allow just the right amount of air into the throttle body at idle speeds. This is done by the work of an actuator motor that electronically adjusts this. When this is not working properly, this may cause a rough idle due to an unbalanced load of air and fuel to be supplied to the motor.

To avoid any unnecessary repairs, I would recommend having an expert from YourMechanic come to your location to diagnose your rough idle firsthand.

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: Cylinder 2 misfire

You need to pull out the coil and check to see if there is oil in the spark plug hole, or on the plug wire boot. If there is, then replace the valve cover and spark plug boots after cleaning...

Q: Possible power steering pump replacement.

In this situation I would suggest getting a mechanic to look at it for you. This way you can avoid replacing parts you don't need. If your system is making a type of moaning noise, if could be a pump...

Q: What does the Engine Overheated -- Idle Engine message mean in a 2012 Chevrolet Equinox?

The Engine Overheated – Stop Engine message can appear on your driver information center (DIC), and is accompanied by a continuous chime. When the DIC displays this alert, the engine is too hot and can cause severe damage. Stop your...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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 P0052 code means This code is seen when the Engine Control Module (ECM) tries to control 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.