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rocky 2/26/2013
2005 Pontiac Grand Am SE 6Cyl3.4L - Engine
Changed out spark plugs, wires, IAC, catalytic converter, but rpm still fluctuates up and then down periodically
Check engine light! "Random Misfire"
1 Answer
  • HouseCallAuto
    HouseCallAuto 2/26/2013
    Too many possible causes to really help you. I have lots of questions also. Would you say that when the engine runs that it is quiet? Do you hear any valvetrain noise / clicking that seems excessive? Was there other codes before the P0300 (random misfire) and if there were , what were the codes? I would replace the fuel pressure regulator as a strong possible cause here. They are well known for going bad on the 3.4 engine and the symptoms fit.

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