What was found
AFTER TAKE OFF, LH ENG FUEL FILTER" FAULT DISPLAYED. CREW COMPLIED WITH ATI QRH PROCEDURES, MESSAGE CLEARED & RETURNED. LT ENG ERRATIC INDICATIONS WERE NOTED. CREW ELECTED AIR TURN BACK TO DEPARTURE WITH AN EMERGENCY DECLARATION. LANDING UNEVENTFUL & NO ADDITIONAL PRECAUTIONARY ACTIONS NOTED.ON ARRIVAL, ACFT GROUNDED. LT ENGINE FUEL FILTER ELEMENT AND FUEL FILTER DIFFERENTIAL PRESSURE SWITCH REMOVED AND REPLACED IAW GE MAINTENANCE MANUAL 73-22-02-404-008-H00 AND BOEING 767 AIRCRAFT MAINTENANCE MANUAL 73-34-01. OPERATIONAL AND LEAK CHECKS GOOD PER BOEING 767 AIRCRAFT MAINTENANCE MANUAL 71-00-00.