As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ATB - CRUISING AT FL340 MACH .82 LEFT ENG ROLLED BACK TO APPROX 65 PERCENT N1 FF 3.0 SAT WAS -57 OVER THE NEXT 20 MINUTES EXPERIENCED SIX MORE ROLL BACKS WITH REDUCTIONS OF N1 FROM 5% TO 60% ALL OTHER INSTRUMENTS INDICATED ROLL BACKS. REMOVED AND REPLACED HMU RAN A/C AT HIGH PWR APPROX 30 MINS ALL SYSTEMS CKS NORMAL, NO ROLLBACKS NOTED. OK TO CONTINUE.