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Q: Random misfiring. Check engine light is on. Running real rough. Bad PCM?

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The check engine light is either on or blinking the engine is running real rough different lights on the dash go on and off and very loud when driving. Wants to stall at idle, shakes badly. Changed out the spark plugs and had absolutely no effect.

My car has 156000 miles.
My car has an automatic transmission.

A: Hi, thanks for writing in. There are severa...

Hi, thanks for writing in. There are several malfunctions that can cause a rough running condition. The spark plugs could be an issue, but it could also be a problem with the ignition, a fuel supply problem, or even a wiring issue. It would be best to have a certified mechanic, like those available at, to perform some diagnostics on the vehicle to identify exactly what is causing the rough running condition.

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