Skip the auto shop - Our mechanics make house calls

Q: Sputter when idle

asked by on

When stooped at the light the truck shakes and sputter as if it's shutting off but doesn't. also it sounds as if the gas pedal is being pressed.
My car has an automatic transmission.

This may be a sign of a failing idle air control valve. The idle air control valve 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 need to get this fixed, I would recommend having an expert from YourMechanic come to your home to replace your idle air control valve.

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
  1. Home
  2. Questions
  3. Sputter when idle

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: Car loses power and stalls/dies if under 2000 RPM

Hello there. There are a few possible problems could be causing your 1999 Nissan 200SX to stall in this manner. The most common would be a MAF sensor, vacuum leak, fuel pump, fuel filter, alternator, battery or oxygen sensors. I...

Q: Car sputters when 1st press on gas

You should have the computer tested and fuel pressure tested to help isolate the problem. You may have a fuel or ignition related problem that needs to be isolated first. The igniter or coil may be not supplying enough spark...

Q: 2004 Nissan Xterra rotor is not turning

Hi there. It does sound you have a broken timing belt. But before you immediately go out to replace the timing belt, the cover should be removed and the belt inspected to confirm that it is actually broken. Even after...

Related articles

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...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
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...