ok so i asked on another from but here might help
my dad has a 2000 f 150 with a 5.4 triton
it had 150k on it and has a bad miss it was horrible pulled codes and it said 4 and 8 were a misfire so we changed coils ran for a while ok then horrible again would hardly pull its self it ran so bad u couldnt drive it in drive
turns out sumhow the whole left side of the motor was flooded out? if you will had water alll around the plugs cleaned that and cleand plugs but when cruising it will have a miss which is noticeable
you stomp on it it goes away
computer is not giving off anycode so we are at a loss here we have nothing to checkhave changed the plugs like last week
so do any of you guys have and idea no matter how obvious tell me and we can check it out sorry for the long post and thanks for any help.... colby

 

I answered your other thread. Try changing the coil boots and using Dielectric grease on them to seal them up.