Q: Rough idle with ac and defrost on

asked by on December 01, 2016

Lately when I turn on the defrost and the ac compressor kicks in the car idles rough. If I turn it off it idles smooth. It also the past few days feels like it wants to stall at idle with defrost on and if I give it a bit of gas then its okay. I've replaced the idle air control valve and cleaned the tb plate.

My car has 256000 miles.
My car has an automatic transmission.

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A rough idle may be caused by many different things such as low fuel pressure, low voltage to the fuel injectors, dirty fuel injectors, a vacuum leak, a faulty Oxygen sensor or a dirty or failing idle air control valve. Any of these possibilities relate to fuel delivery issues that will disrupt the normally balanced air/fuel mixture that would otherwise allow the motor to run smoothly. I would recommend having an expert from YourMechanic cometo your location to diagnose your rough idle problem.

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