What was found
NR 1 ENGINE ENGINE CONTINUOUS ERRATIC AT ALT EPR - N1 - N2 TEMP DECREASING AND SURGING. RETURNED FOR LANDING HOUSTON. REPLACED NR 1 ENG FUEL FILTER AND DID FIND CONTAMINATION. REPLACED 2 AND 3 ENG FILTERS PRECAUTIONARY PER 73-11-01, 405. PERFORMED ENG RUN PER 71-00-501, CHECKS OK.