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Q: My engine idle is high when I start my car

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I don't know if this something new, but I've noticed that my idle is around 1500-2000 RPM upon startup. I heard that normal RPM is around 800-1000 RPM. Is this going to turn into any problem down the road? Thank you!

My car has 100000 miles.
My car has an automatic transmission.

A: If the idle shoots up just after startup th...

If the idle shoots up just after startup then drops down, this is not usually a major cause for concern, and often normal. Although 2000 rpm does seem a little high, 1500 rpm isn't really to out of the ordinary, as long as it drops back down to normal. If this is indeed what it does. Of course, all vehicles will idle high when cold. It is necessary for cold start up. Depending on the outside temperature, it should drop down to normal in a few minutes. Longer if it is near freezing outside.

The throttle bodies on your particular Accord are susceptible to carbon build up. It can make the throttle plate stick. There are also reports that the throttle plate can warp causing high idle issues. Usually these problems make the idle stay high under all conditions.

Other conditions that can cause high idle are vacuum leaks that allow more air into the motor. These can be intermittent problems, but not usually. Some areas to look are around the points that the intake manifold bolts to the head, EGR valve and EGR valve ports, broken vacuum hoses, and a failed brake vacuum booster.

Other than a high idle that doesn't drop to normal, the only problems that should be addressed sooner than later are vacuum leaks. Vacuum leaks can lead to other internal motor damages that will be much more expensive to fix. If the problem persists, you may want to have your high engine idle speed inspected by a professional technician to determine if any repairs are needed.

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