As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK/DECLARED EMERGENCY. ENGINE THRUST BECAME UNCONTROLLABLE DURING FLIGHT SHORTLY AFTER LEVEL OFF. THRUST DETERIORATED ON NR 2 THEN WENT NEAR MAX POWER, REDUCED TO IDLE. NR 1 ENGINE DID THE SAME SHORTLY THERE AFTER. REMOVED AND REPLACED NR 1 HMU PER MT.