As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORT VIA ACARS THAT THE NR 1 ENGINE WAS FLUCTUATING BETWEEN 77 TO 105 PSID, THEN INCREASED TO 178 PSI. THE OIL TEMP WAS INCREASING RAPIDLY. CREW ELECT TO SHUT DOWN ENGINE. MAIN OIL PRESSURE SENSOR REPLACED, AIRCRAFT RETURN TO SERVICE.