As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING A LOCAL FLIGHT THE PILOT ENCOUNTERED A ROUGH RUNNING CYCLE, RETURNED TO BASE AND LANDED EVENTUALLY. MAINTENANCE INVESTIGATION RELEALED THAT THE RT MAGNETO HAD FAILED INTERNALLY. MAGNETO WAS REPLACED AND THE AIRCRAFT RETURNED TO SERVICE. TEARDOWN REPORT TO FOLLOW.