Well I bought a 2005 F-150 4X4 5.4 supercrew last week and thought it was great. This week it started sputtering and bucking if I floored it. It's fine under normal excelleration and idling. I bought it from a local Honda dealership and it came with a 90 day warranty so I took it back to them. Their mechanics could not figure it out so they sent it to the local ford dearership and they had trouble too. Ford said they think they know what the problem is but they want to ask some ford engineers (FOMOCO) before they work on it. At least its all free.

 

Sounds like you got one of the fun problems, let us know what they find.

 

Mine did something like this, but may not be the same. When I would floor it to get on the Interstate or downshift to pass, it would start a rythmic bucking. Like a switch was on and off. There was no sputtering, the tach would go from 2000 to 3000, back and forth. As long as I slowly accelerated it was fine. So, I ordered a set of coils as the truck had almost 100,000 miles on it. By the time the coils arrived, it had stopped. Did that about a week, then quit and has not returned. Never did know what it was.

 

My 06 with the 5.4 did the same thing, I changed the plugs and coils and now it runs like new. It would only spit and sputter under heavy load, if you ran it with a light foot you would have never known there was an issue. Hope they get it figured out for you.

 

Mine was doing something like this. It would buck if I put my foot in it a bit, or if I started going up hill while pulling my trailer. To me it seemed like the tranny was hunting for the right gear, usually when it was downshifting from OD to a lower gear. Took it to my dealer and they found two bad coils. They replaced them and it's been running fine since. Truck has 92K on it.

 

Today my truck also started to backfire and blow out smoke under a heavy load. I couldn't tell what color the smoke was.

 

yeah, my truck has been acting up aswell, if i was holding the throttle 1/4 of the way down the eased it down to 1/2 it would sorta bog and hold back, then jump to 3500 rpms. i have know idea why

 

Well the fomoco seems to think that I need a new clutch package for my differential because it only happens when I floor it. They said that under full throttle the cluches should be engaged and they believe mine are engaging and disengaging which is causing the bucking. Hondas going to buy the clutch package and have ford install it. I'll let you know if it works. Like I said before, at least its free.

 

Ford put the new clutch package in and said it was fixed. I picked it up and it was still sputtering and this time the check engine light came on. I turned around and took it back. The code indicated low cylinder presure in cylinders 1 and 8. Ford now thinks the problem is fuel injectors or coils. Since Honda is paying for all the repairs they were pretty pissed at Ford for fixing something that didn't need to be fixed. I heard from someone that was there that the honda guys were yelling at the ford guys. I think it's funny, a dealership is getting screwed by another dealership instead of one of us being screwed.

 

I had the same thing as Blue Jay described it happened while having about 300 lbs in the bed going 60 and floored it but I can not duplicate it now I wonder if the hard acceleration some how cleaned the spark plugs or something? was going to get new coils and plugs but since I can not duplicate I will wait.
Good luck

Funny with the dealerships ha ha lol

 

Too bad they aren't a member of this site, multiple people already called out the coils.

 

As everyone had said before and what I thoughht; it was the coils. I haven't picked it up yet, but the ford guys said they drove it yesterday and today with no problems. I do have one question, the ford mechanic said he tried to recalibrate my engine (computer) but couldn't because I have 285 tires on it (bought it like that). The mechanic said those tires would cause some rear end damage down the road and that I should go back to the stock tires (255's). Anyone heard of anything like that?

 

bs...

 

I also had a similar problem...went on for over a year. The dealer couldn't diagnose it...until one night...it happened again, and I kept my foot on the throttle!

The repair was a fuel injector, a head, and a catalytic converter. I suspect it was the fuel injector that caused the whole problem, but the dealer couldn't confirm, so I had to pay the extended warranty deductable. Total cost of the repai was around $ 7k.

Regards!

 

i keep having this problem and it keeps being coil #8. Is there anything specific that targets this specific coil and damages it?