ive got the same problem
i thought it was the plugs so changed them and fouled straight away that is all plugs. plugs are at 1.1 but did not miss, and nothing has changed on the car, this problem started at the drag day and two day before it was running fine. so im not sure if its the gap.
took out the coil packs and inspected them but they looked fine, although i did check the resistance and all of them were at 1.9 ohms.
mine happens when i put my foot to the floor/WOT other than that it drives fine. also i can hit 10psi on anything but WOT without any missfiring.
by the looks of it i think its the coil packs just getting too old. but not sure... if anyone can help ASAP it would be greatly appreciated need to get it fixed by next weekend.