What was found
WHILE TOTAL FUEL QUANTITY AND FUEL FLOWS APPREARED NORMAL, RIGHT FUEL QUANTITY SLOWLY PROGRESSED TO READ 600 POUNDS LOWER THAN LEFT TANK. AS CENTER TANK QUANTITY WAS EXHAUSTED TANKS READ 8.59/0.00/7.92. FUEL WAS THEN BALANCED WITH NO SUBSEQUENT ISSUES. GROUNDED - YES. BITE CHECK FQIS OKAY, NO FAULTS LOGGED REF B737-800 FIM 28-41 TASK 801. FQIS TO FUEL STICK COMPARISON. CHECK WAS OKAY REF B737-800 AMM 28-41-00-720-801. FUEL CROSSFEED VALVE FUNCTIONAL CHECK OKAY REF AMM 28-22-00-730-802. OKAY FOR SERVICE.