04 6.0L excursion, engine cuts out
 

my dad has a 2004 ecursion with the 6.0 bought it from the dealership new and now has 260,00+ miles no major issues except the truck used to crank and crank and not start when it was cold, and then it started cutting off randomly when he drives it he had it all fixed 3 months ago after 2 different shops and 3 weeks and dicking around they got it "done" and today he was going to tampa and it cut out twice, so he has his wife bringing it home, he is thinking of trading it in but he loves the truck, any one have any ideas?

truck runs fine but will cut off randomly, highway or in town
used to not start when it was cold
both problems were suposadly fixed* but apparentlky they werent
im thinking he has crap in the trank that is coating the pick up sock, or possibly the fuel cut off under the floor pans is on the fritz, maby the fuel pump?
they had told him it might be his brake pedal assembly, which they didnt even know how to test, any ideas would be great im going to look on alldata tonight and see what i can find, i dont want to take it to a shop if i can help it, and the guess and replace game wont work either
thanks yall!
P.S. glow plugs were already fixed and so was the computer, but it took 2 computers because the first one they got dint work, (at the old shop)

i want to clean the tank and all the filters and check the fuel pressure but i dont want to waste my time

Probably wasting your time with all that...

We need more info about the truck though. How old are the batteries in it? I would have them load tested if they're not brand new, if one is bad replace both. After you've done that, test the FICM. Bad/weak batteries and a dying FICM are 90% of most 6.0 owners cold start issues right there. Try those things first and let us know.

Secondly, a good synthetic oil helps these things tremendously, and adding a couple bottles of rev-x oil additive will do wonders.

I doubt most of the stuff that was already replaced even needed it. That's the biggest issue with 6.0's, finding someone who knows how to properly diagnose them, and most of the time that is NOT the dealer...