hey guys have a prob here hoping one of you guys can help me with this gremlin i have a 97 f150 screw with a 4.6 and 331k on it. about 2 months ago it blew a hole in the manifold (truck was working like a top up until this time) so i changed the manifold and figured while i was at it i would change the plugs and the air filter. after i got it all back together the truck ran like crap sputtering spitting rough idol no power even backfiring and getting cylinder #4 missfire so i put in a new maf no diff. i changed the iac no diff. than i checked my cats and one of them was plugged so i gutted them and wow what a difference. would smoke the tires from a start and peppy as hell just like a new truck. than two weeks later it starts acting like crap again and same cylinder #4 missfire so i figured maybe a bad coil pack. so i took the one from the left and put it on the right and the right one on the left figured if the missfire jumped from #4 to #8 than i would know that it was a bad coil pack but now the truck is running like a top again any ideas?????????????? sorry for the long post hope you can help.

 

Maybe when you changed the plugs you didn't seat the COP well enough but when you did the switch you did?

 

when i switched the coil packs around i never touched the plug end of the wires could the coils have lost their ground and when i switched them around i regrounded them?

 

have you changed the wires? maybe one of them has some corrosion

 

We all agree it is in the plug wires.
Looks like you fixed the problem so I would not worry about it unless it happens again, at which point you will know where to fix it.

 

thanks for the help i will check the wires this weekend wasnt thinking about them since they are only 1 year old but will change them anyway

 

97-00 4.6 F150's have coil packs, COP's came to truck 4.6's in 01'

I've heard of faulty coil packs doing strange things like this too