As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RIGHT FUEL INDICATOR INCREASES IN VALVE WITH FUEL IN CENTER TANK. LEFT FUEL INDICATOR WOULD THE SAME. FUEL WOULD INCREASE IN VALVE APPROX. 10 LBS. EVERY 3-14 MINUTES. REBALANCE WAS ACCOMPLISHED. GROUNDED - YES. GROUND VERIFICATION C/W PER B737-800 FIM 28-21 TASK 815. OPS CHECK GOOD.