I scanned my 2000 grand am 2.4l got code p0300 i changed batt.starter.alternator.plugs etc. Starts and runs now but back fire's, has no power and engine shacks bad ontell About 3000 rpm??
Google obd 2 p0300 battery starter alternator were waste of $. This may have a multiple coil pack for the ignition spark. I would start there. There are quite a few things to consider. I'm surprised there isn't more than random miss fires. That is why I would start at the coil paxk.
change your spark plug wires and coils. also your fuel injectors may be clogged. get a hei spark tester and do a spark test on your coils. You can get coils for 17.98 each at www.partsgeek.com.
your coils are definitely bad.
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