What was found
DURING CLIMB WITH AUTOTHROTTLES ENGAGED AND CLIMB THRUST SET AT APPROX FL10.5 NR 4 ENGINE ROLLED BACK TO IDLE THRUST AFTER ABOUT 10 SECONDS NR 4 ENGINE RETURNED TO CLIMB THRUST. THE THRUST LEVER NEVER MOVED. THE ENGINE OPERATED NORMAL FOR THE REMAINDER OF THE FLIGHT. INSPECTED INLET AND EXHAUST PER AMM 71-00-00, NO DEFECTS NOTED. FOLLOW TROUBLESHOOTING CHART ON AMM 71-00-42, BLEW OUT THE CDP LINE AND CHECKED FOR LEAKS. NO LEAKS OR DEFECTS NOTED. CHECKED AND FOUND FUEL FILTER CLEAN. REPLACED FILTER AS A PRECAUTION. PERFORMED ENGINE RUN TEST 3, THE ENGINE OPS CHECKED OKAY. INSPECTED VSV FEEDBACK CABLE.