96 explorer misfire

[blfontana5100]

I have a 96 explorer 4.0 I have a misfire on #5 I already changed the coil pack the guy I bought it from changed all the plugs and wires 4 months ago and I just pulled the plug thats missing and it is covered in oil and gunk was wondering if anyone could tell me what was going on with that. also I broke 2 wires? when I was trying to get the plug out they seemed to be hollow and very brittle they just snapped as my arm hit them one was a yellow wire from the battery and a green one from sumthin next to the battery.

 

[J_C]

Obviously you need to either replace the entire wire segment that broke or strip it and solder it back together w/insulation over that. Seeming hollow and very brittle is odd, do they look like part of the OEM wiring or something a prior owner added?

I'd guess you either need new piston rings on #5 cyl or the gunk wasn't burning off due to a clogged fuel injector on same cyl., or the plug wire replacement ended up with the wrong wires on a couple plugs.

What does your oil look like, is it getting dark pretty quickly? Does it need topped off a few times between oil changes? Any engine trouble codes showing up? Are they the indication that it's #5 misfiring?

Had the prior owner driven it much (Or at all) since he did the plug wires? Was it running better when you bought it or is this a problem the prior owner faced, then he replaced the plugs and wires, but that didn't fix it? Is it possible he put the wires on the wrong plugs?