Q: Rough idle, missing, almost dies when in gear, shaking violently when driving in low speeds

asked by on September 29, 2016

Husband did tune up. Plugs, egr valve, cops, fuel filter, etc. Noticed a misfire right away. Had codes pulled, cop 2 was misfiring so replaced it again. But now it has continued to get worse. Found a hose that was rotted, replaced it. He's cleaned throttle body, MAF sensor, injectors. We've literally tried EVERYTHING!! Any suggestion on what we might be missing?

My car has 139000 miles.
My car has an automatic transmission.

Hi, thanks for writing in. I’d be happy to provide my insight. I recommend you have the engine checked for vacuum leaks, or and check if carbon is clogging the EGR valve. If you still cannot find the reason the engine is running bad, then my advice is to have a mechanic come out and diagnose the problem for you. I have seen carbon breaking loose and holding valves open, and also I’ve also seen coils for the plugs not firing or shorting out, causing misfires. Try moving the coil in the misfiring cylinder to a firing cylinder to see if misfire moves with the coil. If so, replace the bad coil and coil boot.

If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this issue for you, and make or suggest any repairs as needed.

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