Q: Car rev's fluctuate when idling sometimes, happened twice in one week.

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Twice this week (once while stopped in my garage and once at a red light) the rpm's on my car started to go up and down while I was idling. They would go so low that I thought my car would stall out. The first time was in the garage. I turned my car off and then on again and it seemed to have 'fixed' the problem. When at the red light, once I started driving again, that seemed to 'fix' the problem. What do you think may be causing this being that it's so infrequent.

My car has 209000 miles.
My car has an automatic transmission.

Hi There, What you are describing sounds like a dirty or faulty idle air control valve. The idle control valve reads the air intake into the throttle body and relays this information to the computer which then uses this information to make adjustments to the fueling of the motor. When this is not working properly, you may notice an erratic idle problem as you describe. I would suggest having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.

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