My Mustang has a miss in it, Ive changed the COPs, injectors, and plugs. After changing the plugs I drove it around the block, about 2 miles, the #8 plug turns completely black, its not wet at all just black. The car only has 39K miles, its not smoking or anything. Any suggestions?
Another member reported a similar problem a few months ago. Turned out a mouse had chewed through one of the wires that runs from the ECU to the COPs. Is your GT left outside? Mice love the top of a warm engine when the weather turns cold.