P0300 - (random misfire) only happens when the engine is cold (hasn't been run). I erase the code and restart the engine and the misfire does not happen again. It can be fine all the while the engine is hot and running. But happens again when the engine is cold again
Cars & Trucks - Hummer - H2 - 2003 Hummer H2
Answers & Comments
First start by making sure that the spark plugs are AC Delco plugs or other WILL trigger a P0300. If these are good, the next thing to check is the coolant temperature sensor(ECT). If this is problematic, it will cause too much fuel to be delivered and misfires to occur on all cylinders.