Hello - the engine light came (1998 F150, 4.6L) so had an analysis done. Cylinder #3 is miss-firing. (spark plug and/or wire). Can I just replace the wire for this cylinder? Changing all the spark plug wires is a nightmare on this motor! Is their a source of information anywhere regarding length(s) of wire? Thanks and I'll also post this under the wiring/elec. forum

 

Yes, you can replace just one wire. Normally, it is assumed that if one is bad, then the others are probably ready to go, but it "ain't necessarily so". One of the nice things about the vehicle computer is that it will pinpoint any serious misfire so you can just change it when it does go bad.

I would still buy a complete custom set. You can probably get it on sale, and the factory finished wires are likely to be better. Also, you will be able to replace the others as necessary or convenient, and the computer sometimes doesn't show minor misfires.