Skip the auto shop - Our mechanics make house calls

Q: My car is idling rough and flooding out when first starting. What could be causing this?

asked by on

At first starting. It will be smoking and flooding out. Then seems to get better. Still idles rough and if put it in gear and hold the break it will die from the rough idle. Put new distributor in it and tuned it up. The check engine light is on. Took egr valve off of it and let it run then put it back on and it seemed to help but if let idle for to long it would go right back to idleing rough

My car has 245000 miles.
My car has an automatic transmission.

A: This may be related to a dirty or failing i...

This may be related to a dirty or failing idle air control valve. 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. 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. When the engine RPM drops below the normal range of 750-800 RPM, this may indicate a dirty or faulty idle air control valve.

I would recommend having an expert, such as one from YourMechanic, come to your location to determine why the car is running rough and replace your idle air control valve if needed.

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・Fair and transparent pricing

Get a quote

What others are asking

Q: It has a slight rough idle

You may have fixed the misfire, but the rough idle may be due to clogged injectors and carbon build up on the valves. Try cleaning injectors and throttle body and intake system and see if problem improves. If you the...

Q: Oil loss, can't find a leak, smoke coming from tail pipe and checked coolant this morning was foamy and a different color.

Hello there, there are a few causes for this type of issue. The vehicle should not be driven or started until repairs have been performed. A fault is causing the engine oil and coolant to mix together. When this happens,...

Q: Overfilled oil

I would recommend taking the vehicle back to the service facility that changed your oil and giving them a chance to resolve the issue. This service should no doubt be free of charge since it was no fault of yours...

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...
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...
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.