What was found
DIAGNOSTIC REPORTS NR 2 ENGINE TREND DATA SHOWS A SHIFT IN DELTA CRUISE AND TAKEOFF MARGIN INDICATIVE OF EGT INDICATION ERRORS. ACFT GROUNDED. ELECTRONIC ENGINE CONTROL FAULT HISTORY SHOWED 5 FLT LEGS OF EGT OUT OF RANGE FAULT. CHECKED EGT CONTROL TEMPS AND FOUND S3 TO BE 80 DEGREES HIGHER THAN S2, S1-204.3, S2-170.4, S3-250.8, S4-208.4. GVI OF ENGINE WIRING SHOWED NO DISCREPANCIES. CHECKED EGT PROBE CONECTIONS AND FOUND S3 CONNECTOR AT THE TEMP PROBE TO BE EXTREMELY DIRTY. CLEANED ALL CONECTIONS AND RE-CONNECTED ALL CONNECTORS. CHECKED CONTROL TEMPS AGAIN AND ALL TEMPS ARE WITH IN LIMITS, S1-123.1, S2-70.4, S3-70.3, S4-119.1, ELECTRONIC ENGINE CONTROL BITE TEST PASS, NO FAULTS. REF AMM 77-21-00, 77-21-01.