Ok so you guys may remember my last post about this problem, I have a 2001 5.4l 4x4 and my motor is misfiring, i dont know exactly which cylinder it is but as soon as it throws a code i will report on it. So the last time it went out it was cylinder 7, i bought a new coil and plug for it and had my mechanic put it in and it ran great. and now its raining once again and i drove a whole 10 miles and its misfiring again, I really need some help with this guys, is there something else that could be messing up and causing the misfire?

I cant afford to be replacing plugs every month because of some water, im about to get another vehicle for this rainy weather and park the damn thing.

As soon as it happened i looked under the hood and everything looked dry so i know i didnt romp through the puddles or what-not, i was just driving normal.

 

ok i ran the scanner and its a pending TDC and its misfire cylinder 5

 

This Coil on plug thing sucks doesn't it?

Have you tried just replacing the boots? They're only like $4 a piece and that can sometimes be the problem.

Also, these COPs seem to become more delicate to water, so after you replace the troubled ones you shouldn't have a problem.

I had a #2 misfire from a snowdrift I hit a few months ago, then as soon as I replaced that one #6 went bad too, after replacing those I haven't had a problem since.

 

Also, remember to completely cover everything in dielectric grease, these trucks like that.

 

I have a similiar problem w/ my F150 4.2l V6.I found a crack in one of the sparkplug boots so I replaced the plugs and wires.Still when it rains the engine will begin to miss fire.The first time it happened I got a cylinder 3 miss fire code whichled me to the bad wire.Unfortuntely it will still do it from time to time and it sucks.If anyone has another suggestion I am listening.Thanks