As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMBOUT LEFT ENGINE SURGED TO 100+ N1 RPM, IT WENT BACK TO 60 RPM AND BACK UP TO 100+. RETARDED ENGINE TO IDLE RAN QRC/QRH LEFT ENGINE RUNNING AT IDLE PWR. ENGINE STABILIZED AT IDLE. DIV TIME: 0:14. BITE TEST NR 1 ENG SHOWS MSG 73 20331 FMV DEMAND AND POSITION SIGNALS DISAGREE. ALSO CHECKED EXCEEDANCE AND NR 1 ENG SHOWS PEAK AT 107 AND RED AT 104 FOR 1 SECOND. REPLACED NR 1 ENGINE.