Skip the auto shop - Our mechanics make house calls

Q: Erratic idle - 2013 BMW 335i xDrive

asked by on

Recently, I had my serpentine belt replaced. Since then I have had occasional idling issues. For example, sitting at a traffic light I notice that the idle can drop down to 500 rpm and then revs up to 1200 rpm.

My car has 30000 miles.
My car has a manual transmission.

A: This is a common sign of a dirty or failing...

This is a common sign of a dirty or failing idle air control valve. This is a unit that monitors the air intake as it is mixed with fuel prior to being injected into the motor at low speeds or at idle. This unit also assists with the deceleration process as you let off the gas pedal bringing the engine back down to an idle. When this is not working properly, you may experience an erratic idle as you describe.

I would recommend having an expert mechanic, such as one from YourMechanic, come to your location to determine why the idling is erratic and repair 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: Dont no think injector

This may be a result of 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...

Q: Revving out of control

It sounds like you may have an issue with your idle air control valve on your 2011 BMW 328i. The idle air control valve is responsible for keeping the RPMs within a certain range during idling at a stop. If...

Q: Violent jerking wether in drive or not rpms go extremely high then down for a few minutes before shutting off

This may be related to the fuel injectors which is a common issue among the 335i turbo BMW's in addition to failing turbo waste gate bushings. I would recommend taking it first to the dealer to see if they are...

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...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...