[Redlinez]

My sons Grand Prix GTP had random multiple misfires and wouldn't run for crap all of a sudden. The recently replaced his intake gaskets, plugs, and wires. No check engine light was on, just had oil leaks. He threw a fuel pump at it because his friend said there wasn't enough coming out of the schraeder valve when he pressed it. A new mass air flow sensor fixed it. Go figure. A "surefire" indication that you have a bad plug wire besides specific cylinder misfire codes (and that can be a valve issue, intake leak, etc) is if you find white areas on the wire where it gets next to any metal.