Originally Posted by 99STM
I don't believe it is the fuel pump. It will lean out at half throttle but I think that is because the map needs some work. I only did probably one WOT log last night and that was when the CEL started flashing for the Cyl. 1 misfire. On the way home last night, I would slowly give it more throttle and watch the wideband and the boost gauge. At 13psi, it will start to physically stutter and misfire. The AFR's were rich were a little rich, but not a whole lot. I am going to regap the plugs today and see what happens. This is also the first tank of gas and there was still a gallon or 2 of 91 in the tank when I filled it. I don't think that would cause the problems we are suffering though. At this point, I am fairly convinced it is a mechanical issue. If regapping does not work, I am going to pressure test the inlet. If that doesn't work, coil packs would be a good place to start and I will probably start on Cylinder 1 since that's where we got the misfire.
What I did was switch the ign coil from the cylinder that was misfiring to another cylinder... if that cylinder (the one you switched the coils with) has a misfire, then you know the coil is bad.