What was found
NR 1 ENGINE FLUCTUATIONS DURING CRUISE. ENGINE FLUCTUATED BETWEEN APPROX 82 AND 96 FOR APPOX 5-10 CYCLES. FEEDING FUEL FROM MAIN TANK NR 2 FOR FUEL BALANCE. PERFORMED AN ENGINE STALL/SURGE CHECKLIST. ENGINE RETURNED TO NORMAL. ENGINE CONTROL LIGHT ILLUMINATED AFTER NR 1 ENGINE SHUTDOWN IN CHOCKS AND THEN WENT OUT AGAIN. DURING QRC ACCOMPLISHMENT FLUCTUATION CONDITION AFTER AUTOTHROTTLE DISENGAGED. REDUCED POWER TO APPROXIMATELY 60, FLUCTUATIONS STOPPED. CHECKED CDU, FOUND RECENT FAULT NR 1 ENGINE. FMV DEMAND ON FLT LEG NR 1. REF FIM TASK 73-00. REMOVED NR 1 ENGINE HMU IAW 73-21-10-000-801-F00. INSTALLED HMU IAW 73-21-10-400-801-F00, OPS CHECKS AND LEAK CHECK GOOD. REF EA 800-73EA-09160.