What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS AFTER SETTING TAKEOFF EPR OF 1.05, LEFT ENGINE LAGGED WHEN FLEX PWR STEP, REJECTED TAKEOFF AT APPROX. 50 KIAS. NO OTHER ABNORMALITIES NOTED. MAINTENANCE ACCOMPLISHED AMM 71-00-00-011-B 13 ACCEL/DECEL FOR LH ENGINE. ACCEL TIME LIMIT GOOD, OK FOR SERVICE.