dodgeboy11

I have a 2006 F250 with the 5.4 with 182k miles and I'm stumped. The truck idles fine but after driving for a while it suddenly stops accelerating right...giving it more gas just makes it slow and even backfire. If I shut it off and restart it I get full power for several more miles. It is giving codes 171, 174, 191, and 2006. It has a new MAF sensor, fpcm, air filter, ran fuel injector cleaner through, plugs look good. Yesterday I went 60 miles before it started acting up. So frustrated. Any ideas? Thinking maybe junk in the gas tank or something? Should note it starts at random times and speeds but will get worse until I can't maintain speed and have to restart it. Also should note it has a bad exhaust maifold giving codes 420 and 430, too so I don't think it is the cats or something like that.

miniceptor86

Do you have to wait a while after you shut if off like time enough for something to cool down or are you able to basically stop and then restart and it's OK for a while? Sounds like a fuel system problem to me, fuel filter but not familiar with the vehicle so do not know if there is an inline filter or just the "sock" in the tank. Maybe something else is causing a reduced fuel flow over time.

jdinner

Sounds like the way mine was acting.
https://www.f150forum.com/f4/06-5-4-...-fires-291476/

This catalytic converter has two sections in it. The forward chunks break up and move around to clog the ports in the second section.

dodgeboy11

Only have to have it off for 5 or ten seconds and it is good for several more miles. Fuel filter is next up....easy access under the truck. But it seems unlikely as it should be more consistent.

dodgeboy11

With a leaky exhaust manifold shouldn't have this issue, though, right? And only off for 5 seconds shouldn't cool them down enough, would it? I might still try dropping the exhaust, though...what do I have to lose?

lewissa81

If you haven't figured this out yet, inspect out the FPDM.

jdinner

We would all appreciate an end to the story for people with the same problem in the future. It's very frustrating to read a thread with no ending.

PerryB

My truck recently started hesitating under acceleration and it was the fuel filter. When blowing backwards through the old filter, the restriction was obvious and a bunch of brown sludgy crap came out.