What was found
(CAN) ON APPROACH, NR 2 THRUST LEVER WOULD NOT GO BACK TO IDLE. AUTO THROTTLE WAS ENGAGED AT TIME AND NR 2 LEVER STOPPED 1 TO 1.5 FROM IDLE (58 PERCENT N1) AUTO THROTTLE DISENGAGED CORRECTLY BUT STILL NO MANUAL MOVEMENT OF THRUST LEVER AFT. AUTO THROTTLE WAS ENGAGED AGAIN AND DISENGAGED. SYSTEM RETURNED TO NORMAL AT THAT TIME. CREW ELECTED TO RETURN. THE SYSTEM COULD NOT BE FAULTED BY MAINTENANCE, NOR WAS THERE ANY EVIDENCE OF SOMETHING BLOCKING THE CONTROLS. THE AUTOPILOT COMPUTER SHOWED NO FAULTS. THE SYSTEM WAS CHECKED SERVICEABLE.