Low fuel rail pressure ONLY once Engine warm?

Hello, have a 2008 F350 with the 6.4 and 130K. Stock, except an Edge tuner, which is currently flashed to the factory settings. Truck runs great when started up cold, throws no error codes and has plenty of power. However, once the engine comes up to temperature, the next time the truck is started it throws both the P0087 and P2291 codes and the truck is sluggish. This issue persists until the truck engine is cold again, like sitting overnight in the summer or after a few hours in the winter. If the engine is restarted while still cold, no issues. Happens every time, and has gone on for over a year. Changed fuel filters, no impact. Anyone else have this issue? What sensor(s) might "communicate" between the fuel rail pressure and the engine/coolant temperature. Appreciate any and all ideas! :fustrate:

is all emissions equipment intact

I have not taken anything off with emissions, though as I bought it used, maybe it has an EGR ****** kit on it already... not sure what to look for to confirm...