Pontiac Repair: misfire cylinder #1, blown head gasket, pontiac sunfire

Question
I have a neighbor that has a 2001 pontiac sunfire with a 2.2 3speed automatic with a misfire on #1 cylinder. He had a blown head gasket so I took the head off and had it machined and pressure tested. It passed the pressure test but was warped. Put the car back together and runs great down the road, but at idle it has a misfire on #1 according to my scan tool. I just finished up last night on the car real late so I havent been looking at the car today. I wanted to get your opinon on the matter before I go any further. Now I put new plugs wires gaskets on the car. I have a snapon inline spark checker that i put on the plug and it seems to be firing but dont know if the coil is bad.  Like I said it runs great down the road but at idle it has a rough idle and misfire. Thanks for your help Jason

Answer
Hi Jason:

Which 2.2 liter the Eco tech or the older sytle 2.2 non overhead cam engine? The older 2.2 has the coils sperate and you can swap the coils the ecotec you can't. But if you just have a single cylinder misfire I doubt it's a coil due to the fact a coil woul effect the companion cyliner. Did this engine hydo lock when the head gasket blew? If so it couls have a bent connecting rod It may not make noise but it will effect the compression on that cylinder. You could have an injector that's lean causing the issue and wiggleing the fule rail around you may have distirbed some dirt in the rail and it may have plugged an injector up? You can try swapping injectors around. if that doesn't work then do a cylinder leakage test and see how much leakage you have on that cylinder The coolant in the cylinder may have damaged the bore and or rings and you have a loss of compression too. Good luck :)