What was found
IN CRUISE LEFT DUCT PRESSURE 45 RIGHT DUCT PRESSURE 5. GROUNDED - YES. COMPLETED B737-800 FIM TASK 36-10, FAULT ISOLATION PROCEDURES PARTS 1-8,10-25. TESTS INCONCLUSIVE. NO DEFECTS NOTED AT THIS TIME. ACCOMPLISHED PNEUMATIC HEALTH CHECK REF NG-36WC-00001. EXCEPT LAST 2 STEPS (PG 17 OF 33). NO DEFECTS FOUND. PRECAUTIONARY CHANGED: 390 AND 450 THERA SENSORS: REF B737-800 AMM 36-11-05 AND 36-12-03. PERFORMED ENGINE BLEED AIR CROSSOVER OPS TEST PER AMM 36-11-00 LH/RH DUCT PRESSURE 42-45 PSI WITHIN LIMITS OPS CHECK GOOD AT THIS TIME. ENGINE BLEED AIR IS GOOD FOR ETOPS SERVICE.