[stepside83]

well i changed the plugs back to the factory plugs, and still runs like crap still misfires, any other ideas as to what would cause this still? is there a way yo test to see if one or any of the coil packs are bad? would bad co2 sensors make check engine light come on, and or flash, yes when i really get it on the truck around 4000 rpm the light comes on not all the time and flashes and then goes out, any idea what would cause that? thanks guys for all the info so far please keep it coming