Misfire under stress

[mattstansbury]

01 3.8 N/A 115,xxx miles..Gutted cat, new AC delco plugs&wires less than 10k miles ago..
Misfires under load @ 4k-6k rpm. So waited until night and opened hood, during slow rev, nothing..but a quick burst showed a bright light, not sure EXACTLY where it was coming from, but i'm thinking a cracked coil pack? thoughts? I'm going to go to local shop and have them check witch cylinder is misfiring.

[FordMan77]

I'd say either a cracked coil or a bad plug wire. I know they're new but even new parts can fail.

Check the coils around where the bolts are that hold them to the ICM. I had one crack on both sides around the bolts and it shorted so badly that it fried my ICM and shut me down on the side of the highway with no notice. Just like someone turned off the key. It would run, but on about 4 cyls.

[mattstansbury]

Im going to have codes checked, as the service engine light did start flashing..and figure out which cylinder(s) is/are misfiring and focus on those plugs&wires and coilpacks..and i've seen some crazy stuff with sparkplugs, my friends truck had one where the sparkplug looked perfectly fine, but when it was flipped upside down, the electrode would fall down and hit the tip thus creating no gap for spark lol.