What was found
WITH NR 4 CROSS FEED VALVE INDICATING "OPEN", NR 4 TANK (QTY) WENT DOWN AS IF CROSSFEED VALVE WAS CLOSED. NR 4 TANK BOOST PUMP LOW PRESSURE LIGHTS DID NOT FLASH, ENGINE NR 4 FLAMED-OUT. DESCENDED TO FL 300 AND RECYCLED NR 4 CROSSFEED VALVE, ALL ENGINE INDICATIONS/OIL PRESSURES WERE NORMAL FOR INFLIGHT RESTART. NR 4 ENGINE RESTART WAS SUCCESSFUL, TOTAL SHUTDOWN TIME WAS 2 MINUTES. ALL ENGINE PARAMETERS REMAINED NORMAL FOR THE REMAINDER OF THE FLIGHT. PERFORMED WINDMILL INSPECTION OF NR 4 ENGINE IAW AMM 72-00-00, NO DEFECTS NOTED. DE-ACTIVATED NR 4 CROSSFEED VALVE PER MEL 28-05, NR 4 CROSSFEED VALVE LOCKED IN "OPEN" POSITION AND TRANSFERRED TO DI. REPLACED CROSSFEED VALVE ACTUATOR PER AMM 28-22-02.