My misfiring experience...
My car, 2000 M6 SS, 25000 miles, bolt-ons only w/ some nos.
One day out of the blue it started misfiring under any load, however it idled fine.
I combed the engine bay looking for vac leaks, none.
Cleaned air filter and maf, still misfired.
Read codes and here's what I got, some I knew were already there due to my exhaust setup ( no cats
)......P0135, P0155, P1133, P1153. These I plan to get tuned out in the future. However I got the obvious P0300 which indicates "Random/Multiple Cylinder Misfire."So, I figured I'd start at the source of the problem and work my way up the ignition system. I replaced the plugs and wires and low and behold, problem solved! What's weird however is that neither the old plugs or wires that I took off looked bad. It's just crazy how something so simple can make the car run so bad.

