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Q: 2c9d code and misfires on the cylinders 4, 5, and 6.

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Massive valve cover gasket leak...vehicle had a pre cat 02 code 2c9d....gasket replaced....code still there now misfires on 456

Hi there. The oil could have gotten on the spark plugs causing the plugs to not fire. Take out the spark plugs and see if they are covered in oil. If they are clean them off with carburetor cleaner and put them back in. Then retest the condition. If the plugs are not covered in oil, then check the spark plug wires and make sure that they are pushed in all the way. For the light being on, check the upstream O2 sensor for any broken wires. If you need further assistance with your misfire, then seek out a professional, such as one from Your Mechanic, to help you.

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