What was found
INFLIGHT DUCT PRESSURE DIFFERENTIAL EXCEEDED 20 PSI AT 8000FT LEFT - 40PSI RIGHT - 65PSIAT 17000FT AND APPROX 10 MINS INFLIGHT LEFT - 45PSI RIGHT - 55PSIAT 34000FT AND APRROX 25 MINS - 30 MINS INFLIGHT LEFT - 45PSI RIGHT - 45PSIAT 34000FT AND 3.30 HRS OF FLIGHT TIME LEFT - 40 PSI RIGHT 40 PSI. GROUNDED - YES. T/S #2 ENG. PER B737-800 FIM 36-10 TASK 807. FOUND PRSOV LEAKING. PERFORMED OPS TEST OF PRSOV PER B737-800 AMM 36-11-04-860-003, OPS CHECK FAILED. REMOVED AND REPLACED #2 PRSOV REF AMM 36-11-04. OPS AND LEAK CK GOOD. PERFORMED ENGINE RUN FOR OPERATIONAL LIMITS PER AMM 71-00-00. OPS CK NORMAL.