As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE PERFORMING T/C 78273000 FOUND MAINT MSG NR 77-20871 (THE TOP LEFT EGT SIGNAL OUT OF RANGE) FOR NR 1 ENGINE. GROUNDED - YES. CW FIM 77-21 TASK 804 AND TC 78273000. BITE CHECK OF NR 1 AND NR 2 ENGINE SHOWED NO RECENT FAULTS AND NO HISTORY FAULTS. THIS CLEARS PLT.