Have an 04 f350 4x4 with 6.0. When I got the truck was told by ford mechanic that had ran test on it and said hpop was bad, it would start cold but not warm. It would run as long as the rpm's were not allowed to drop, once rpm started down engine would die and not restart.
Changed hpop all the pipes except the u shaped ones in the back and the best I can tell will have to pull motor to change those.

Now the question could the rails themself leak? The same problem I had when I got the truck. Icp has been replaced with ford icp. The man I got the truck from had just had four of the injectors replaced, and right after truck died and had to be towed in. Truck runs and idles fine as long as it is not hot, it will idle for hours as long as rpm stays constant. Have yet to pull the rails off either side.


Thanks.

 

Sounds like a high pressure oil leak for sure, but not a bad HPOP. If the pump was bad it likely wouldn't run at all. The branch tubes are a pain to replace, the trans and flex plate have to come off of the truck, then you can change them. Bob is far more knowledgeable on the earlier high pressure oil systems, I'm sure he'll chime in here...

 

Is your truck an early 04 or a late one , before or after 9/22/03???? One of the first things I would check is the new injectors, we just got a 03 f250 for my nephew and th guy had put 8 brand new injectors in it and was having same problem you are, wound up that one of the brand new injectors FROM FORD did not have the Oring in top of injector sealed, had the oring but not the clip to keep it in shape and in place.
If it is a late 04 then did you replace the Dummy plugs as well?? The early 04s have 5STC fittings but thy are not known to fail regularly, but it is possible for the seals to get torn if not installed properly. If you have seen the oil rails just let us know what they look like, a straight tube/log/ or kind of like a pretzel.
Any time you have a HPOP?? problem the first and easiest test to do is to just unplug the ICP sensor and see if it helps, a faulty ICP can make it do stupid things.
Also I would highly reccomend doing an AIR test on it to see if you realy have a HPO leak.