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cylinder 5

  1. Misfire on all rear cylinders. 1-3-5.

    Buick Enclave
    2009 Buick Enclave CXL AWD with 98k. I have a noticeable misfire with codes reading misfire on cylinders 1,3 and 5. All coils have been replaced and all plugs are new. I also get a code reading catalyst system below effective threshold. I replaced the O2 sensor on the back side, pre catalytic...