Q: Engine idles rough and jumps between 500 and 1200RPM when shift from Drive to Reverse; Check engine light on

asked by on May 20, 2016

The engine seems fine most of the time but it idles rough and occasionally jumps between 500 and 1200 rpm when I shift to drive or reverse. When I throttle and it hits 4000 rpm, the 'Check Engine Light' starts flashing. Can you give me advice as to what to do to fix all of this?

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You may have a couple of separate issues:

  • The flashing Check Engine Light under heavy load is most likely an ignition system misfire. This could be something like a coil pack or worn spark plugs. These engines are known for going through coil packs so that would be my first guess.

  • The rough idle could be related, but it sounds more like a vacuum leak or possibly a faulty idle air control valve (IAC).

The first step is to retrieve the diagnostic trouble codes for your Check Engine Light which serve as a starting point for any further diagnosis. I suggest you have a trained professional, such as one from YourMechanic, diagnose your vehicle firsthand.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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