I'm stumped. I have an 03 mach 1 with 28k miles. it runs good most of the time but when coming to a stop it sometime drops down to 500 rpm or lower and then jumps back up but it has never actually died. hooked up my diablo and it threw a few codes. misfire at startup, misfire on cylinder 3, and cylinder 5. and it said bank 1 was lean. Again NEVER does it when driving just when coming to a stop. What could be causing this?