CM870 misfire under load

[Blackout26]

Hello all. Been a guest for a bit now. Recently purchased a 2005 Kenworth with a CM870, 565HP & 1850TQ. Previous owner demandated it by unplugging the egr. Said he didnt get it tuned and there is a block plate on it. Truck has always loped at idle, performance wise ran great. Yesterday morning I felt a drop in performance and a dead misfire under load. This happend loaded just before Wolf Creek Pass. I stopped and changed fuel filters no change. I continued on, about half way up when everything got some heat it, it stopped. Pulled full boost 32 psi 900 on the pyro. Come down the 25mph side on the jake and hit the flats and it came back. No black smoke during misfire, no white smoke. Boost wise seems to only lose 2-3 pounds during misfire, however there a significant power loss. So, here is a list of things I've done before posting.
Fuel filters = No change
Pressured up fuel tank and checked for external leaks = No leaks
Electric lift pump, key on runs for 2 minutes then shuts off. = good
Pulled valve cover and checked valve train and lash and injector injector adjustments = good
Drove to the local dealership and they gave me a fault print out for free.
Active faults
PID-94 FMI-1 Flash code 2215 or 482
Fuel pressure low -Data valid but below normal operational range - moderately serene level Or Fuel pump delivery pressure - Data Valid but below normal operating range - Moderately Servere.
Fuel level in tanks makes no difference. I think that rules out pickup tube ?

I don't have the compucheck fittings to do fuel pressure checks or access to Insite without paying for it. I can purchase the tools. If I gotta take it to a shop I will, however I would really like to fix this myself.

I appreciate everyone's time.