Ive got a 1997 ford f150 and I had the problem where it was missing on the 4th cylinder and we fixed the problem and the code went away, but just recently the check engine light came on and I plugged up the scan tool and it threw the code of missing on #1. The spark plugs have recently been changed not even 2 weeks ago, I plan on getting new wires soon, but if that doesnt work, what could be the problem?