What was found
REPEAT GRIPE. ON T/O ADVANCED POWER TO STANDARD, NO RESPONSE ON NR 1 ENG. NR 1 ENG SHOWED EPR, N1, EGT, N2 FROZEN. FUEL FLOW MOVED 100PPH. AFTER QRH REJECTING T/O PROCEDURES AND THROTTLES AT IDLE N1=23 PERCENT, EGT 500 C, N2=47 PERCENT. AFTER RETURNING TO THE GATE FOR MAINTENANCE, THROTTLES AT IDLE SHOWED N1 ON NR 1 ENG WAS 10 PERCENT LOWER THAN N1 ON NR 3 ENG. AFTER SEVERAL THROTTLE ADVANCEMENTS NR 1 ENG RETURNED TO NORMAL OPERATION. (OPEN)