Skip the auto shop - Our mechanics make house calls

Q: My car rough idles and stalls, but no check engine light.

asked by on

When I use my car it idles at 700 and then stalls when used for 5 min but there are no check engine lights. It was tuned up 2 months ago changed fuel filter and when we took it out a lot of air came out instead of gas. We changed the fuel pump right after and cleaned the engine with seafoam. And it still stalls. What can can be wrong with my car?

My car has 206000 miles.
My car has an automatic transmission.

A: This issue is normally caused by low fuel p...

This issue is normally caused by low fuel pressure or a faulty injector, but since you have just replaced the fuel pump, this may also be a sign of a failing idle air control (IAC) valve. This is a unit that is located on or near your intake manifold that monitors the air intake as it is mixed with fuel prior to being injected into the engine. 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. However, when the engine RPM drops below the normal range of 800 RPM (for most cars), it is more than likely that you are dealing with an IAC valve problem. In cases where this valve is clogged or is nearing its replacement age, your vehicle will stall instead of idling after the release of the throttle. If you'd like assistance with this issue, a certified YourMechanic technician can come to your location to help inspect your vehicle's rough idle or replace the IAC valve for you.

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: Skyline GTR R33 Engine swap with Chevy 383 small block, will it fit?

With a large enough budget, you can get just about anything in there. You will need more than just an engine to make everything work like the engine control module from the donor vehicle with a wiring harness installed in...

Q: Why does my car get poor fuel mileage and not rev over 1000 rpm. 2006 Honda Accord

Hello. You are on a pretty good track for diagnosing this problem. I would usually start by checking the computer for codes. This would be the best indication of what is going on as it may be a sensor issue....

Q: Timing chain valve is bad

A worn timing chain can cause some camshaft timing to become erratic and cause a host of engine running issues. However, there is a tensioner on the lower part of the engine that is supposed to remove the slack automatically...

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...
How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.