What was found
AFTER PUSHBACK AND DURING CONFIGURATION BEFORE TAXI, THROTTLE WENT FULL FORWARD TO TAKEOFF POWER WHILE BRAKES WERE SET, HANDS WERE NOT ON THROTTLES, HAD TO FORCEABLY PULL THROTTLES BACK TO IDLE AND FINALLY HAD TO DISCONNECT AUTOTHROTTLES, RETURNED TO THE GATE. INTERROGATED MAT NO FAULT FOUND FOR LAST 2 LEGS, NO EICAS MESSAGE, NO STATUS MESSAGE RELATED. PERFORMED AUTOTHROTTLE SYS GROUND TEST, AUTOTHROTTLE SERVO LOOP TESTS PASSED, ALSO GROUND VERIFIED AUTO THROTTLE & THRUST MANAGEMENT COMPUTING SYS OPERATION NORMAL FROM MAT IAW AMM 22-31-00-5. SHUTDOWN ACFT ELECTRICAL POWER, POWERED ACFT WITH NO FAULTS. ACFT OK FOR SERVICE.