As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED: FUEL; ON TAXI OUT CENTER TANK QUANTITY FLUCTUATED, PASSING 2000 FT CENTER TANK QUANTITY DISAPPEARED, MAIN TANKS SHOWED DECREASE QUANTITY INDICATING USE. PILOT ELECTED TO DO AN AIR TURN BACK AND LAND AT STA: KMIA. AIRCRAFT LANDED WITHOUT NO FURTHER INCIDENT. MAINTENANCE IS IN PROCESS OF TROUBLESHOOTING THE AIRCRAFT FUEL QUALITY INDICATION SYSTEM.