98 Dakota single cylinder misfire following overheating

[98dak0ta]

I'm having problems diagnosing why my #4 cylinder is misfiring and burning through plugs, so I thought I would turn here. Specs of my truck are 98 Dodge Dakota, 5.2L V8, 150k miles, very little problems overall so far.

Heres the short story, I got a small hole in the radiator on a trip which caused slight overheating, I was able to shut it off before the needle was all the way in the red. After I filled the radiator up and started to pull away, the engine was misfiring horribly. I kept driving it and it got smoother but never as it was before. Made it to the shop, they put a new radiator in, and I asked them to do a quick diagnosis of the rough running and he said it was the fuel injector because he couldnt feel it "ticking" like the other ones. So I took it home and I replaced the fuel injector, plugs, wires, cap and rotor. It ran better but not as smooth as before. One of the things it does that is different is right when I let off the brake from a stop to accelerate, the whole truck hops up and down a little. After about 6-8k miles after the tune up, the check engine light came on. Checked the code, misfire in 4th cylinder. Pulled the plug and the gap was huge, like barely any tip left. I was hoping it was a bad plug, so I replaced it. Same thing in around the same amount of time. This is obviously telling me there is something going on and I need to figure it out! My brother, who is a boat mechanic, brought a compression tester home and said it was good, but we did it at night after a couple beers so who knows if thats accurate.

Anyone have any ideas of maybe where to start? Thanks in advance!

[theFREAKnasty82]

try rechecking your compression during the day time and when you're sober!
All jokes aside, you might have a blown head gasket. Something else to consider, you could have burnt valves. Also if you can have a cylinder leakage test performed; make sure that your valves are straight (not cracked) or any other problems.

[98dak0ta]

Im gonna have it looked at next and tested next friday, hopefully it wont blow up before then! I pulled the #4 plug today and found that the gap was fine but the plug was very copper colored and extremely hard to get out (and I did use anti-sieze when I put them in). I put a new one in there and it made it no better, possibly worse. Ugh Well see what the shop says, but it doesn't sound like it will be cheap!