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Q: Car sporadically idle high & runs around 1500 RPMS

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My car has been sporadically idling high. It frequently runs at around 1500 RPMs when it is in Park and even when it is already warmed up. After taking it to the mechanic’s shop, they cleaned the idle motor control (not sure if that is the name for it). After they cleaned it the frequency of the problem seemed to grow less for a short while, but then it went back to idling high more often. I have not found any pattern, nor any consistency to the idling problem. It happens in any type of weather and any temperature. Can you give me advice and suggestions in finding the cause and the solution?

A: Hi there. The most common causes of this on...

Hi there. The most common causes of this on your vehicle are either a bad idle control valve, a dirty or failing throttle body, or a vacuum leak. It is very common for the engine to have a vacuum leak at the intake manifold gasket. I usually start by checking that first for leaks. If it is fine, then I clean the throttle body and check it for wear. If that is fine, then I replace the idle control valve. If you are going to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose the high engine idle speed.

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