What was found
DURING TAKEOFF FROM MIA, RT ENG STARTED TO ROLL BACK 2-3 PER N1. AFTER TAKEOFF FLUCUATED BETWEEN 2-3 TO 6-8%. BY 500FT IT WAS BOUNCING BETWEEN 95% & 68%. UPON THRUST REVERSER APPLICATION R ENGINE WAS 8% LOWER. CREW DECLARED EMERGENCY (EDC) AND PERFORMED AIR TURN BACK (ATB) TO MIA. AFTER LANDING MTX GROUNDED A/C AND ACCOMPLISHED HIGH POWER RUNS ON LEFT AND RIGHT ENGINES IAW B767 AMM 71-00-00. N1 STILL FLUCTUATES 2-3 % MTX STILL TROUBLE SHOOTING. PERFORMED ENG RUN UP AT IDLE AND T/O POWER INDICATION WERE NORMAL, N1 IND. WAS FOUND STABLE WITHIN NORMAL READINGS NO FLUCTUATION WAS NOTED REF AMM 71-00-00 ACFT REMAINS NO ETOPS.