Oldsmobile/Buick Repair: ENGINE MISSED BAD AFTER WARM UP, pontiac grand prix, fuel injection system

Question
MR. MCMILLIAN,

I HAVE A 1995 PONTIAC GRAND PRIX THAT HAS A LIGHT MISS WHEN COLD BUT AFTER IT HEATS UP TO NORMAL OPERATING TEMPERATURES IT GET MUCH WORSE. I'VE CHANGES THE PLUGS, WIRES, FILTERS ECT... BUT IT STILL HAS THE MISS..NO ARCHING ANYWHERE..NO TROUBLE CODES SET. ANY HELP WOULD BE GREATLY APPRECIATED. THANKS.

Answer
hi robbie. well first we need to isolate the mis to one cylinder.it really sounds like you may have a coil pack going out.you need to pull each wire off the coil pack one at a time each one you remove should create a drop in rpm,s.one of them will have no change rather the wire is on or off this will be your miss.now we have to isolate a fuel prob or secondary ignition problem.to do this simple the wire you have off is there spark at that coil terminal.if yes fuel prob if no coil prob.replace that coil.if all this checks out write back i will tell you how to troubleshoot the fuel injection system.please take a minute to rate my help it is very important    ty  billymac