What was found
AIRCRAFT NOT GROUNDED: PILOT REPORTS INCORRECT FUEL TANK FUEL BURN: ALL PUMPS (6) ON, FULL MAIN TANKS AT GATE: LEFT 8.6 / CTR 8.7 / RT 8.5 / TOT 25.8. TAXI: LEFT 8.6 / CTR 8.7 / RT 8.1 / TOT 25.4. CENTER TANK FUEL BEGAN TO BE USED ONLY AFTER RT TANK AT 8.1. WHEN CENTER TANK EMPTY LEFT MAIN TANK 8.1 / RT MAIN TANK 7.8. POSSIBLE UNWANTED FUEL TRANSFER WING TO CENTER TANK. MAINTENANCE TROUBLESHOT UNWANTED FUEL TRANSFER FROM RIGHT MAIN TANK TO CENTER TANK IAW FIM 28-21-00-810-813. TRANSFER FUEL AND TURN ON RIGHT PUMPS ON. CANNOT DUPLICATE FAULT. NO UNWANTED FUEL TRANSFER NOTED.