What was found
NR 1 N1 ROLLED BACK TO 25-35 % JUST PRIOR TO DECENT. A NOTICABLE AND AUDIBLE BUMP IN AIRFRAME, LT YAW, & CONFIRM ENGINE OUT ON MCDU'S. SHUTDOWN ENGINE IAW QRH. ELECTED TO LEAVE ENGINE SHUTDOWN DUE TO POSSIBLE DAMAGE. EGT & N2 SLIGHTLY LOWER THAN NR 2, 3. FF 770 PPH PRIOR TO SHUTDOWN . NR 1 THROTTLE UNRESPONSIVE . NR 1 ENG LOW PRESSURE BLEED AIR CHECK VALVE, FOUND STUCK OPEN. R & R PER MM 36-11-01-4-1, PERFORMED FULL BORESCOPE & CHECKED WITHIN LIMITS PER MM 72-00-07-06-1. R & R NR 1 ECU PER MM 73-21-02-4-1, R & R NR 1 ENGINE HMU PER AMM 73-21-01-4 RAN NR 1 & 3 ENGINES PER JRH, PERFORMED NR 1 ENGINE 40% POWER ASSURANCE TEST PER AMM 71-00-00-5-1.