As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW WROTE UP THE LT ENGINE FOR ACCELERATING MUCH SLOWER THAN THE RT ENGINE. TROUBLESHOT TO THE HMU. REMOVED AND REPLACED WITH AN OVERHAULED UNIT. RAN ACFT AND COMPLETED A MAINT CHECK FLIGHT. ALL CHECKED OK. TWO FLIGHTS LATER, CREW WROTE UP LT ENGINE NOT MAKING POWER AT ALTITUDE. .5 THROTTLE KNOB SPLIT AT FL 350- LT ENGINE SLOW TO ACCELERATE. REPLACED THE HMU WITH A SERVICABLE ASSY, RAN AND COMPLETED CHECK FLIGHT. ALL CHECKS OK.