This is a pictures of plug and ignition coil with 75,000 miles on it that misfiring normally. No large deposits, not discolored. Reddish or green deposits indicate burning coolant. Black, sooty deposits indicate burning oil.Also check for hairline cracks in the white porcelain insulator.

A common reason for misfires, hesitation, and stumble is a corroded ignition coil and/or plug wire.Ignition coil and spark plug inspection.


This example is from a 3.1 / 3.4 liter engine. Burned / corroded coil tower or corroded plug wire

can cause misfires under hard acceleration, or when cruising at a steady speed (45-65 mph)

then accelerating to pass.

Also will misfire at idle on wet, damp mornings. This also causes a check engine light code P0300.

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  • Guest - Lorraine

    I have a Nissan SX 200 1995 and I just had my car serviced the transmission and oil changed also in previous and prior to that did the spark plug change and hoses as well and currently my car is overheating and I don't know why what are some tips that you can help me with I'm afraid to go to a mechanic just for a diagnosis and how much they charge being a female I'd like to be more or less correct about what could it be so that way when they do let me know what the problem is I am paying for my car to get repaired and not paying for one service and then again coming back for another type of service