As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FOUND MAGNETO FILTER DEFECTIVE WHEN SUBJECT TO MAGNETO P-LEAD VOLTAGE OR HIGH TENSION LEAD TESTER VOLTAGE. REGULAR OHM CHECK DID NOT PICK UP DEFECT. ENGINE WOULD RUN INTERMITTENTLY BAD ON THIS MAGNETO. THIS IS AN AFTER-MARKET PART INSTALLED IN LINE WITH P-LEADS TO REDUCE MAGNETO P-LEAD VOLTAGE INTERFERENCE.