As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INTERMITTENT ENGINE VIBRATION DECENDING THROUGH 10000 FEET. SECOND TIME WE HAD AN ENGINE FAULT INDICATION AS WELL. VIBRATION COULD BE FELT ON THE RUDDER PEDALS WITH ADDED THRUST ON THE LEFT ENGINE. PERFORMED VIBE ANALYSIS. VIBES REMAIN IN ALLOWABLE LIMITS DURING ENGINE RUNS. NO FUALTS PRESENT DURING ENGINE RUNS.