As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER LEVEL OFF AT FL 360 NOTICED DUCT PRESSURE SPLIT RIGHT 42 LEFT IS 15 WHEN THRUST REDUCED LEFT PRESSURE INCREASES TO 18 PSI NO OTHER ANOMALY’S IDLE THRUST DESCENT SHOWS 18 PSI ON BOTH. REMOVED AND REPLACED LT ENG PRSOV REF AMM 36 11 04 LEAK CHECK AND FUNCTIONAL CHECKS GOOD. ALSO PERFORMED ENGINE IDLE RUN CHECK NO DUCT SPLIT NOTED.