Speaking of easy things to try; I apologize in advance, but I was wondering if you know the last time the fuel filters were changed . Again It is a stupid question , but like my dad used to say to me; (KISS it) "keep it simple stupid". Sometimes it's the simplest things we overlook.:tu::c::humm:

P2552 -P2552 FICMM FICMM circuit — throttle/fuel inhibit circuit RPM out of range for closed pedal position

Whatever the hell that means...? Still sounds like a FICM issue?

Mudstrokin - I just had very similar issues to you, no power, and it got better when warm. Truck ran awful though, ended up being injector #4 was bad on mine.

Crewed - The filters were done about 3k miles ago... I've pulled up 2 new codes from yesterday to today :argh::argh::argh: Now i'm getting a
P0272 - cylinder 4 contribution/balance fault
P0284 - cylinder 8 contribution/balance fault
:argh::argh::argh::argh::argh::argh::argh:

Mdub - Thats what i'm afraid of.... how much did you pay for your injector? Advance told me 235 per injector:ouch: and i haven't seen many sites on here taht sell injectors for 6.0

It could also be the glow plug controller.??

Chrysler OEM Parts | Dodge, Jeep, Chevrolet Genuine Parts, GMC, Pontiac, Buick, Hummer, Cadillac, Nissan, Ford, Lincoln Mercury, Kia & Suzuki

That code?? i cleared it while driving and it popped back up again in a couple min....

When mine was having serious issues, I had P0275,P0273,P0335 &P0611. I was also loosing coolant. After some new head gaskets for the coolant leak, and a glow plug controller, those codes are all clear. I do still have the P2552 code. I'm thinking it's a loose wire or something of that nature; as I didn't have it before the dealer visit, and it was there when I picked it up from them.:argh:( of course when I took it back to them there diag.computer doesn't show any codes, and they could care less what y SCT says):ouch::c:

How much did the glow plug controller cost? and how did you come to the conclusion that that was your problem?? And did it run like shit b4 you replaced it then better after?

The dealer replaced it 'cause it was still under warranty. :yeah: It did run rough until it warmed up though.:argh:

This might be worth a try.:humm:
2005 Ford F250 Diesel controls
:c:

Did the dealership pin point the problem for you or did you figure it out on your own? when its cold it cranks up in about 3 seconds runs rough for a second then has loss of power while driving until it's at running temp

I thought it was a FICM issue when I took it in. It took almost 10sec. of cranking before it would fire up. It seemed like a gasser with a real bad miss until it warmed up. The dealer actually figured it to be the gpcm. Don't forget that mine had bad HG's, and was loosing coolant also. Normally there are some really excellent techs on this site. You could try a post on diesel in distress before trying alot of new parts without being sure, as nothing for the 6.0's are very cheap.$$$:scare2::c: