Q: Why does my car have rough idle and lack of power only on warm days?

asked by on

Hi, my car has n very rough idle and lack of power, but only on warm days. Why is this not happening on cold days?

My car has 90000 miles.
My car has an automatic transmission.

This problem may be caused by a coolant temperature sensor, idle air control valve, throttle position sensor, or O2 sensor that may be failing. Use a digital volt ohm meter (DVOM) to check resistance on all of the sensors. If a sensor has no resistance, it is a sign that it has failed. Check the harness plugs for any debris, moisture, oil, bent pins, or broken wires.

If you need further assistance, then seek out a certified technician, such as one from Your Mechanic, to check and replace the coolant temperature sensor, idle air control valve, throttle position sensor, or O2 sensor that is faulty.

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. Why does my car have rough idle and lack of power only on warm days?

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 shakes in par and when put in reverse

Hi. The concern you are describing for your 1999 BMW 318i sounds like that of a worn engine or transmission mount. The transmission and engine mounts have rubber bushings inside of them which dampen the engine vibrations. The mounts are...

Q: Check engine light on & car delays

If all of these trouble codes are related to the throttle body, I would recommend having your vehicle's throttle body inspected by a qualified mechanic who is proficient at engine diagnostics. This inspection would check the throttle body for any...

Q: Acceleration automatically.

Hi there. There is an issue with the engine having a vacuum leak and the may be cruise control is coming on to accelerate the engine. First check for any vacuum leaks on the engine. If the engine is running...

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...
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...