Skip the auto shop - Our mechanics make house calls

Q: Rough idle when A/C on

asked by on

Lately I've noticed my 2004 infiniti fx45 idles rough when the a/c is running and I'm idling at a light; to the point where it feels it may shut off. When a/c is off car runs strong or when I'm driving with a/c on it runs great. It only has issues when I'm in idle. Any idea of what the issue could be?

My car has 214000 miles.
My car has an automatic transmission.

A: Your engine throttle body and idle air cont...

Your engine throttle body and idle air control may be clogged with carbon and engine is idling too low with A/C on causing the rough idle. Have the idle control valve and throttle cleaned out. You may also have the injection system cleaned and the combustion system cleaned to reduce carbon buildup on the back of the valves. If you want to have this looked at, a certified professional from YourMechanic can come to your car's location to diagnose your rough idling issue and let you know what needs repair.

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・Save up to 30%

Get a quote

What others are asking

Q: Truck runs really rough, smells like antifreeze in the cabin, testing said it was O2 sensor, and there is an overheating, hissing noise

Hello. You can possibly rent a cooling system pressure tester from a local chain auto parts store. With the engine off, remove the radiator cap and pump the cooling system to no more than 10 psi. You will be able...

Q: Passenger's side window not working

Hi. This issue is usually caused by a switch on the door. It can be the individual window switch or the master driver side switch. I would have a mechanic visually inspect the window to come up with the proper...

Q: Idle speed control value

Hi, thanks for writing in. I'd be happy to help. This is a case of an idle air control valve not working properly. An idle air control valve literally bypasses air around a closed throttle plate inside the throttle body...

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...
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...