Need Help from Powerstroke Gurus

[btracy]

I have a challenge for you powerstroke Genius's.
I am hopping to get some help diagnosing my 1997 F350, Powerstroke with manual transmission.
Here is what it is doing:
Rough idle. Rough running up to 2000rpm. loss of power. Bad mpg. Down to 12mpg or less from 16-18. occasional surging while driving under no load.If you try and hold the rpms at 1800 it will stay there for about 5 seconds and then increase to 2200 and steady.
Here is what I have done so far:
Fuel filter is changed every two oil changes.(3-5000 miles)
Pulled all injectors and had them tested and re-sealed. Replaced one injector with re-manufactured. Replaced harnesses under valve cover. Replaced valve cover gaskets. Checked and cleaned all harness connections.(PCM, IDM etc.)
No codes.
I have an AE scan Tool program. Here is what I have tried and or noticed.
Cylinder Contribution. Never lists the same cylinders. Always 3 random. When running this test it always goes through two cycles on all 8 cylinders and then reports. On occasion it will only go through one cycle(of 8) and then show only one cylinder fault. One other note in regards to an above symptom,when holding at 1800 rpm and it spikes to 2200+ the voltage or the pedal position(monitored by scan tool) does not change.
Sorry for the long post just trying to get all the info.
Thanks to anyone who responds.

[btracy]

An update for anyone who can help. I have removed and cleaned the fpr valve. I have also replaced the idm from another good running powerstroke. Still cannot get a consistant cylinder cont. test. Frustrated!!
Thanks.