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.

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?
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. Erratic idle - 2013 BMW 335i xDrive

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: Q: how can i fix it

Engine coolant can leak externally through a hose, radiator, water pump, etc. or internally due to a leaking head gasket and sometimes a leaking intake manifold gasket depending on the engine design. External leaks are typically found by simple pressure...

Q: Q: VALVE Cover GASKET Replacement

Hi there. Assuming, the valve cover gasket was properly replaced. The smoking under the hood, may have been residual oil burning off the exhaust manifold. The white smoke seen coming through the grill, may have been the snow turning to...

Q: Q: Overheating

Based on your report, you have that unenviable circumstance where a fault has multiple causes. That is, you are indicating that the thermostat replacement did offer a partial resolution but obviously not a complete one. Of course, you do want...

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 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...
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...