As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) INTERMITTENT ROUGH RUNNING ENGINE IN FLIGHT. MAGNETO'S CHANGED EARLY FOR 500 HR INSPECTION. ON REMOVAL FROM ENGINE, SUBJECT MAGNETO NOTED TO HAVE EXCESSIVE END PLAY ON GEARSHAFT. OVERHAUL VENDOR CONFIRMED END PLAY, OIL THROUGH OUT ASSEMBLY, BEARING BORE IN DISTRIBUTOR BLOCK HOUSING WAS OVERSIZE. CONTACT ASSEMBLY'S WORN BEYOND LIMITS. UNIT OVERHAULED.