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Q: RPMs max out

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When I start the car, the RPMs ramp to max. I changed the ECM, throttle body, throttle position sensor, and cam position sensor, but it still does the same thing.

A: Hi there. If the throttle body is fully clo...

Hi there. If the throttle body is fully closing then this is either caused by an electrical short or a vacuum leak. If the throttle body is not fully closing then the throttle cable may be binding. I would suspect a vacuum leak. This may be caused by a loss or broken vacuum hose, a bad gasket or possibly an EGR valve that is stuck open. I typically run the engine and listen for any noses making a hissing sound which indicates a leak. Once those are eliminated, if the problem occurs I do a smoke test to see if I can find the leak. It can also be one of the other sensors, but that is not as common. If you were looking to have this repaired, consider YourMechanic, as a certified mechanic can come to your office to diagnose why you are having abnormally high RPMs.

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