As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSTALLED ELECTROAIR ELECTRONIC IGNITION 61000-5M TO REPLACE LH MAGNETO ON PIPER MIRAGE WITH LYCOMING TIO-540-AE2A ENGINE IN NOV 2018 PER STC FOR TURBOCHARGED LYCOMING ENGINES. EXPERIENCED SIGNIFICANT INTERMITTENT MISFIRING AT HIGH MANIFOLD PRESSURES, 37-42" ON TAKEOFF AND OTHER HIGH POWER OPERATIONS. UNABLE TO DIAGNOSE/RESOLVE PROBLEM WITH MANUFACTURER. REMOVED EIS MAY 2022 AND RE-INSTALLED SLICK 6363 MAGNETO. NORMAL HIGH POWER OPERATION RESTORED.