2000 F350 7.3 appox 285k. All stock
Problem started a month ago and have been chasing my tail ever since. Problem first started coming home one day and truck started running very rough and lost all power. I was just a couple block from home so i let it roll in the drive.

The first thing i went after was a bad leak at the dip stick oil pan nut. would loose a lot of oil and drain the engine causing it to starve for oil. Installed a retro kit on the outside of the pan and replaced the tub as well. Performed a complete oil change and tried to start.No luck
Second tackle was to check the injector oil deflector pipes. After cracking on the engine for a while (note: oil pressure switch never bounced on the dash) i began to see milky oil coming out of the pipes. I did find that a glow plug wire pinched in the valve cover as well(replaced the valve covers). Truck began to hick up and if i held the accelerator pedal to the floor the truck would run for a while and die but the throttle was 100 percent and the rpm's were 800-1000.
Third I inspected the hpop reservoir and found it empty. From my knowledge that should be supplied from the lpop. I ordered a new lpop and pulled the old one. Found a slight scratch across the plate but nothing that would cause a total loss of oil flow. After replacing it with the new one i tried to get it to fire up again no luck.
Forth I bought a low pressure oil gauge and tested during crank and found no pressure. I had an older 7.3 (97) that had a stuck closed lpop pressure relief valve in the oil cooler, and i started to wonder if it could be a stuck open valve dumping off all the low pressure oil. Pulled the oil cooler to inspect the valve. It was in working order, so I resealed the cooler and reinstalled it.
A quick check I left the hpop reservoir plug open and cracked for a while and i began to see oil coming out pretty fast. so I pulled it and tried starting it again. It tried and looped for a while i held the throttle and nothing really changed. I looked in the hpop reservoir again and found it empty again.
Fifth task was moving to the high pressure side thinking that the hpop is sucking the oil out of the reservoir to fast to replenish it or blowing it by internally. Talked to a friend that works as a cat tech and has owned a few 7.3's as well and came to the conclusion that we need to put an hpop on it. Ordered a used one at 120k and a new external seal kit for it. After installing the new pump tried to get it started again. This time with a little luck it started running but very rough again. I tried to purge the air out of the hpop side and still ran very rough. My friend came over and we took it for a test drive and floored the engine a few times. Got most of the air out and ran half way right but the truck would shake every once and a while as if an injector was cutting out. If you keep it in OD then the truck would shake hard at 50 mph but if you dropped it out of OD you could barely feel it. And some times it went away completely.
Sixth item was the injector seals. After getting back from the test drive we discussed that maybe it was the loose wire on an injector from when i changed the valve cover gaskets or a bad o-ring on a couple injectors, causing the long crack in the mornings or after it sits for a couple days. So a couple days later i drive it to his house with new seals for the injectors. Spent 6 hours pulling all injectors and resealing them. Tired to start it with the valve covers off first. After a few minutes of purging clean oil started to come out the the injector discharge pipes. and ran half way ok considering the injectors were all opened up. but then the clean oil from the injectors turned milky and the engine started running rougher. We reassembled the rest of the engine and tried to take it for a test drive. No luck the engine ran worse than before, missing and no power had to keep it under 2k on the rpm's or it would starve for oil in the hpop.
Lastly number seven i checked my ipr (note ipc has already been changed) with another working ipr stem. Bench tested both and both worked well.

In conclusion i'm a bit lost of what to do next. any advise would be greatly appreciated

 

Cracked cups methinks.

 

I can't see how the cups would have to do with the oil issue. Please explain?

 

You have milky oil coming out of your injector. That indicates fuel and oil mixing and possibly coolant as well. You said you replaced injector o-rings so the only thing left that would allow mixing of fluids is cracked cups. What's the contents of your degas bottle look like?

 

I should have clarified. The milk oil coming out of the injectors is air mixed with the oil. The coolant is clean and not changing levels.
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That changes things. It can take awhile for air to work itself out of the oil galleries after the HP oil system has been cracked open. Monitor IPR Duty Cycle and ICP while the engine is running rough and see what the numbers are. You can do this with FORScan on a laptop and an OBD dongle, a Scangauge II, or any device compatible with the J1850 PWM protocol.

EDIT: I thought I read in your original post that you had no codes. I was mistaken. Pull codes with a compatible scanner to narrow things down quicker.