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.

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 1,000 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!
  1. Home
  2. Questions
  3. Rough idle when A/C on

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 rough idles and worse when engine is warm - 2008 BMW 528i

Hey there. You should first check for any problem codes. Next, check for vacuum leaks. Third, check out the idle air control valve - clean it if possible. A professional mechanic, like one from YourMechanic, can help with this diagnosis...

Q: I have an engine light code P0507. It says that there is a high idle issue with my vehicle.

Hi there. The code P0507 means that the idle air control valve (IAC) is registering a higher rpm than normal. Check all of the vacuum lines to the engine. A small vacuum leak will cause the engine rpm to be...

Q: In mornings before work (cold usually), my car acts like it wants to stall in idle/park. Give it gas 1-2 minutes. No more issues

Hello and thank you for contacting YourMechanic. What seems to be happening is the EGR valve is sticking open and when it gets hot, the valve shuts. This will cause an engine to stumble when first turned on. Anther thing...

Related articles

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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.