What was found
NR 1 ENGINE N1 INDICATION BECAME UNSTABLE DURING CLIMB. REPEAT WRITE-UP. THEN EGT EXCEEDED LIMITS AT 952 DEG. THEN FUEL FLOW INDICATION BECAME UNSTABLE WITH SURGING AND YAW. PULLED TO IDLE N-1 AND FF INDICATION REMAINED UNSTABLE BUT SURGING STOPPED. PERFORMED FADEC BITE TEST AND PULLED FAULT CODES NOTHING ABNORMAL FOUND. REF TSM 73-21-30. BORESCOPED HPT STAGE 1 AND 2 PER 72-00-00-6, NO DEFECTS NOTED. REMOVED AND REPLACED HMU REF AMM 73-13-00-4. REMOVED AND REPLACED NR 1 CIT SENSOR REF MM 73-21-02-4. REMOVED AND REPLACED N1 SENSOR IAW MM 77-11-01-4 05. REMOVED AND REPLACED FUEL FILTER AND THE TEMP INLET SENSOR (T 1.2). REF AMM 73-12-02-4 AND 73-23-06-4. HIGH PWR RUN PER JRH.