As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 ENGINE PT 5.4 PROBE WAS FOUND INSTALLED WITHOUT BLANK. AS EPR INDICATION SYSTEM IS NOT INSTALLED ON THIS AIRCRAFT, THE OPEN PORT ALLOWED HPT OUTLET GASSES TO IMPINGE ON THE CORE COWL (TITANIUM). SLIGHT LOCAL HEAT DISCOLORATION AND SOOT DEPOSITS FOUND. IT APPEARS THIS ENGINE WAS CONFIGURED FOR A/C WITH EPR SYSTEM. (BORESCOPE PLUG IS NORMALLY INSTALLED).