As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
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. TSR COMPLETED, FOUND S4 EGT PROBE OUT OF LIMITS, R & R PROBE REF 77-21-01, PASSED EEC TEST REF 73-21-00.