my 99 gt has developed a misfire, you can feel when driving, it threw a code, misfire on cylinder one. has new plugs. at idle it seams as if nothing is wrong. i tried swapping the coil between cyl 1 and the one next to it, but same thing still. i was going my the haynes manual to find which was cyl 1, is it possible that theres a difference. anything else i can check?