As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED (SOMEWHERE NEAR PDX) AT FL370 NR 3 ENGINE "FLUCTUATED" FOR ABOUT 10 MIN. SPEED WAS .86+,THEY NOTED THE FUEL FLOW WAS SLIGHTLY LESS THAT THE OTHER ENGINES, N1 WAS 80.6 - 82.2, N2 WAS 83-85, EPR WAS 1.13 - 1.20. REPLACED NR 3 END N1 TRANSDUCER PER MM.