As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
OWNER EXPERIENCED INTERMITTENT ROUGH RUNNING ENGINE IN FLIGHT. EXPEDITED NORMAL LANDING. UPON INVESTIGATION, FOUND RIGHT MAG RUNNING ERRATICALLY. MECHANIC INVESTIGATED MAGNETO AND FOUND DISTRIBUTION PIN IN DISTRIBUTOR CAP LOOSE. REPLACED DISTRIBUTOR AND WORKED PROPERLY. BUT UPON RUNUP, FOUND LEFT MAG RUNNING ERRATICALLY. FOUND SAME PROBLEM IN DISTRIBUTOR CAP OF LEFT MAG. REPLACED AND BOTH MAGS WORK PROPERLY.