Pontiac Repair: 97 Firebird 3800 P0300, crankshaft position sensor, spark plug wire

Question
I have a 97 Firebird 3800 5 speed that misfires and backfires constantly at any engine speed. I cannot drive it. The only code I can get from it is the P0300 random misfire detected. On live data, the ignition advance is -10 to -30 degrees. This condition started as intermittent and is now constant. I'm thinking it is either the IC or crankshaft position sensor. Your professional input would be greatly appreciated.

Answer
Hi John:

a p0300 is just a "random" misfire a true scnan tool not a code reader can read which cylinders are misfiring and at what rate they are misfiring. If it's a pair of cylinders misfiring it can be a IC module a coil or even a bad spark plug wire will do take out one coil pack. if you narrow it down to which coil is the culprit you can swap the coils around and see if the misfire follows the coil or stays put. You could have a mechanical issue too I have seen 3800 engines break valve springs and cuase all kinds of strange issues too Usually an intake valve But that is premature I would persue an eletrical issue first and foremost. Pull all the plug wires off one at a time and see if any are rusted or burnt on the coils that is a tell tale sign as well. That is where I would start looking. good luck :-)