What was found
IN SMOOTH AIR, 2.5 HRS INTO FLT, FUEL IMBALANCE NOTICED WITH NO CONTROL INDICATION, WING NOT HEAVY ETC. FUEL QTY, 7.3, 8.3, 8.5. BALANCED FUEL NORMALLY, TOTAL FUEL QTY NORMAL AND MONITORED FOR REST OF FLIGHT. APPEARS TO BE AN INDICATION PROBLEM. DURING DESCENT IMBALANCE RETURNED OPPOSITE, BELOW 10,000FT. SUSPECT LT GAGE ERRATIC INDICATION. ACFT GROUNDED. TSR ISSUED. COMP PROBE AND 12 EA TANK UNITS REPLACED. OPS AND LK CK IS GOOD.