What was found
DURING CLIMB, LT DUCT PRESSURE READ 50 PSI, AND RT DUCT PRESSURE READ 25 PSI. 25 PSI DIFFERENTIAL. DURING CRUISE, BOTH RT AND LT DUCT PRESSURE EVENTUALLY READ 45 PSI. ACFT GROUNDED. WHILE PERFORMING ENG BLEED AIR LEAK CHECK REF MM 36-11-00-700-802. FOUND PRSOV LEAKING AIR. REMOVED PRSOV REF MM 36-11-04-000-201. INSTALLED PRSOV IN REF TO AMM 36-11-04, OPS CHECK AND LEAK CHECK GOOD. GROUND VERIFICATION GOOD. ACCOMPLISHED PART POWER LEAK CHECK IAW AMM 71-00-00-700-823-F00. BOTH ENGINE PARAMETERS ARE NORMAL NO DUCT SPLIT NOTED IAW AMM 36-00-00-860-804.