Ok here is the story.Back in October someone was so kind to put sugar in my wifes F-250 with a 5.4 well since then the insurance co has put new fuel pump,tank,and all injectors,fuel filter and did a upper end carbon burn.Well it ran good for about 20 miles and the same thing.Hesitates so bad from an idle that it shakes and bucks.No engine codes,no leaks of any kind,it has had new plugs also.I have been reading alot about the COPs in these things.Its weird you can be driving and it will be missing then it clears up for a few secs and then back...Im not sure if its fuel or spark issue.Its going back to the shop agian on monday.Boy oh boy is my insurance co going to be mad.They have put $3200 in this thing so far....Any ideas would be greatly appreciated.

 

I'd say look at the fuel system first and then move on to checking the coils. I had one go south on my truck and it threw a code. It also ran horribly below 3k rpm's. Good luck.

 

What else would u look at on the fuel system?It has New fuel pump,filter,injectors.my only question is when these cop crack where do they crack it and how bad.Are they small hairline cracks or are they busted open?

 

i had a CO2 sensor go bad in a 97 f150 with a 5.4. sometimes it would start missing and about die then other times it would be perfectly fine. replaces all the factory sesors with boshe sesores. runes great now.

 

Thanks for all the ideas.I changed out the #4 and 8 cop and they had small hairline cracks on the bottom of the coils.I then pulled the rest of them out and inspected them.Well i found 4 more cracked.And it looks like someone at one time had changed a couple of them.I put the worst one out of the 4 in the #1 cylinder.Well the wife drove it and it poped a misfire #1 I then talked to the repair shop and they said it was #2 when they worked on it.But i changed all the coils around.So i might be on to something.I have to go get some new coils today and see.