Just seein if anyone has some ideas before I start throwin parts at this thing, My 95 6.5 vin F runs great when its cold, but when it warms up and I get in to the throttle and the boost hits 10psi it immediately drops to 0psi and the truck just blows black smoke until either I coast for a bit or stop then it will build boost again as long as I keep it under 10 psi.
(new relocated PMD, New vac pump, strait piped, very little play in turbo, EGT runs aboet 400-450 deg.)

 

Boost solenoid is likely gummed up and when commanded to vent keeps doing so,spray some WD40 in the vac ports of the solenoid or replace it with AC Delco.

Would also be a good idea to check and clear the trouble codes.
google paper clip trouble code test.