In my 03 5.4L I did plugs and new boots about 30-40k miles ago because I was getting the common miss when it would rain or wet out. Problem went away and has been fine ever since. Well recently the miss has started back up again when it rains or is real damp out but goes away once the truck warms up. I plan on doing plugs and just replacing all the boots again.

Im not getting any CEL when it misses so I'm not sure if it is a coil pack itself that is going bad or just time to do plugs and boots. If I do decide to change all the coil packs this time, what brand is the best to go with?? truck has 115,000 on it also

 

The brand of COPs isn't critical. Cheap eBay COPS work OK.

I would be more concerned with the spark plugs themselves. What brand did you use? These engines (for reasons that no one has ever been able to adequately explain) seriously seem to prefer Motorcraft platinum plugs. I hear a lot of stories about V-8 and V-10 engines developing a hesitation and misfires after 10-20k miles with an aftermarket spark plug.

As for the CEL, you won't get one unless you practically have a dead cylinder. What you need is a code reader that can show you the pending codes. This will point you to the misfire.

 

I used autolite plugs last time I did the swap.

Ill have to hook up my programmer and see if there are any pending codes in it.

 

i used autolit triple platinum plugs 30k ago and it runs just as good now as it did with Ford plugs. I do add dielectric grease to my boots, COP wire plugs just incase water gets past the oring in the plugs