My wife's grand prix started misfiring and has gotten progressively worse to the point that it wont stay running. The only code it throws says misfire on cylinder 6. Ive replaced the plug, wire and injector on that cylinder with no luck and i swapped the coil pack with another one and the miss didnt move. Anyone have any ideas for me? I have a hard time thinking its a sensor or a cat because from my experience those will throw a random misfire code, misfire on multiple cylinders code, misfire on bank such and such code etc as opposed to a miss on a specific cylinder
