What was found
ON CLIMB OUT THROUGH 9000 FEET; AIRCRAFT SHUDDERED AND ENGINE #1 N1 BEGAN CYCLING THROUGH 80% AND 90% N1. ENGINE REDUCED TO 50% N1 AND ENGINE INDICATIONS WERE NORMAL AT 50% N1 AND BELOW FOR REMAINDER OF FLIGHT<[01] ACCOMPLISHED BORESCOPE INSPECTION OF #1 ENGINE BOOSTER PER AMM 72-00-00-200-803-F00; HPC PER AMM 72-00-00-200-803-F00. HPT BLADES PER 72-00-00-200-807-F00; LPT PER AMM 72-00-00-200-808-F00. NO DEFECTS NOTED BEYOND AMM LIMITS. REMOVED AND REPLACED HMU AND MAIN FUEL PUMP PER MT 773-11-00. NO FIX . REMOVED AND REPLACED #1 ENG REF MT 771-00-01 TTG8Q0064PHE. OPS AND LEAK CHECKS GOOD.