What was found
NR 4 ENGINE FLAMED OUT 200 MILES FROM JFK, TRIED RESTART AT FL 310 AND AT FL 180. NOTICED FUEL PRESSURE AT 50 PSI . ON RESTART ATTEMPT, NR 4 N1 DID NOT ACHIEVE FLIGHT IDLE. N1- 23 PERCENT, EGT 238 , F/F 600PPH. ACCOMPLISHED NR 4 MAIN FUEL TANK NEGATIVE PRESSURE CHECK. REMOVED AND REPLACED MAIN FUEL FILTER AS PRECAUTION. RAN ENGINE, OPS CHECK NORMAL.