Engine miss fire on bank one

Discussion in 'KJ General Discussion' started by ImmrRich, Sep 14, 2020.

  1. ImmrRich

    ImmrRich New Member

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    Hello everyone. My 2005 liberty 3.7 has 280k on it and the engine had a loss of power and popping thru the intake so I found a wrecked 2005 donor jeep and swapped out the engines and the donor ran like a top so I put it in and it runs the same way! I used all the same sensors, coils, injectors and intake from the donor and it runs the same way! I checked out the wiring harness and grounds and they're all good. I even got another pcm and that didn't make a difference! It doesn't throw a check engine light either! Anyone have any ideas?
     
  2. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    Welcome to the forums.
    The new PCM was it correctly programmed?
     
  3. ImmrRich

    ImmrRich New Member

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    Thanks and yes it was. It runs the same way with both PCM's.
     
  4. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    This is a strange situation. Something is not right.
    Mechanically speaking, popping noise back thru intake generally relates to intake valve, valve spring, or a guide that is toast but the engine was run on a stand & was fine?
    Maybe Too much back pressure? Check for plugged cats/ exhaust?
    Test compression, and do a cylinder leak down test?