Hi was wandering if this could be either my alternator, coil or something like that when i get my engine under the hood area wet when either mudding or just hosing my engine out, I have noticed my rpm gauge moving up and down and truck is sluggish when put in drive from park. It then goes away, its temporary it must dry out. i don't think it's my air intake because I have taken it off and covered that up when hosing out and I have already cleaned out my tp sensor because it had some mud in it. My model is a 1997 4X4 4.0L 93,000 miles Any problems with solution would be appreciated.

I see this thread is old, but... my truck did something similar. Turns out i had a minute crack in the coil pack. It would get wet and run crappy. By the next day it dried out enough to run normal. Trying to find the problem I swapped out coil packs. That's when I was able to see the crack just under the plug.

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Stock 3.0 1wd w/manual trans. Pioneer Premiere head unit, 2 x 12" Fosgate P3, MB Quart 1500.1D amp, 4 pioneer premier 6 1/2"s, 4 channel V-Power Alpine highs/mids.