As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLIMBING OUT, LT DUCT PRESS 16, RT DUCT PRESS 36. N1 ON BOTH MOTORS 100.8. CRUISE AT FL380 LT DUCT 22 RIGHT DUCT 36 N1 90.3 ON BOTH ENGINE. ACFT GROUNDED. ACCOMPLISHED NR 1 ENGINE BLEED AIR HEALTH CHECK REF. T/C NG-36WC-00001. REPLACED NR 1 ENGINE PRECOOLER CONTROL VALVE. OPS/LEAK CHECK NORMAL REF. AMM 36-12-02. NO OTHER DEFECTS NOTED.