What was found
AFTER LEVEL OFF AT FL380 AND APPROX 18 MINUTES INTO THE FLIGHT THE "ENG 1 FUEL" CAUTION LIGHT ON THE OVERHEAD PANEL ILLUMINATED, INDICATING "EITHER FUEL FILTER BLOCKED OR FUEL OVERHEAT" IAW THE AIRPLANE FLIGHT MANUAL THE NR 1 ENGINE THRUST LEVER WAS REDUCED TO IDLE AND CLEARANCE FOR A LOWER ALTITUDE AND RETURN TO DEPARTURE WAS REQUESTED. NO OTHER ENGINE MALFUNCTIONS WERE INDICATED WITH N1, N2, ITT, OIL PRESSURE AND FUEL FLOW ALL STABLE. THE LIGHT CANCELLED DURING THE TURN AND DESCENT AND THE FLIGHT CONTINUED TO LANDING WITH NO FURTHER INDICATIONS OF MALFUNCTION.