Runs great cold, horrible when hot.
 

I am pretty much out of ideas what is the issue with my truck. But here it is.
2004 F-350 6.0L late build - no
Back story

Started to get coolant pukage and had over 16psi pressure. Tore down the engine and found the PO used black onyx gaskets. Already had studs. Had heads machined and put everything back together. Truck ran great before the build. This is where the fun begins. No STC fitting.

Issues

Trucks starts up no problem hot or cold. Runs great when the truck is cold. Has tons of power. Once the EOT gets above 120F it falls flat on its face. It runs really rough, lopes and misses and shakes the whole truck. It has absolutely no power. It will not rev. above 1500RPM in drive but will rev. no problem in neutral or park. In drive the truck will barely move. Has no boost either. Truck does not smoke at all. A slight smell of unburnt diesel but that's all. At first I was getting contribution / balance codes. No the same code back to back other than #5 and no more than 2 at a time. Replaced #5 injector but still randomly getting #5. I could start truck, pull codes, reset, turn off, start the truck again and have a different code each time. Totally random. I loaded up my SCT Extreme street tune and truck acts the exact same way expect I do not get any codes.

TLDR - truck runs great cold, but horrible when warm. Seems to be temperature related.

Attempted solutions and PIDS.

Double checked push rods and rocker arms. All good.
Replaced #5 injector. Code still randomly comes up.
Replaced IPR valve - connector on IPR broke during build
Replaced ICP and pigtail. ICP builds under WOT correctly.
IPR stays around 24%
HPOP replaced last November.
New stand pipes and dummy plugs. No STC fitting.
All new orings and copper washers on injectors.
Polished spool valves with 1000grit wet sand paper.
Replaced FICM harness. Connector to #5 was damaged and could of shorted out.
Fresh oil change T-6
Fuel pressure stays at 60psi under all conditions.
Cleaned EBP and MAP.
FICM voltage stays between 47-48 under all conditions.
battery(s) test out good.
Alternator puts out 14
Passed bubble test
Passed buzz test cold/hot


I think that covers everything. Might of missed something.

It's possible you could've gotten a bad ipr. I'm not sure it would do just that but it's a thought being that it's duty cycle stays the same


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Problem solved. FICM was bad and all 8 injectors failed contribution / balance test on IDS.