HouseCallAuto 2/26/2013Too 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.