As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON THE FIRST FLIGHT OF THE DAY, TAKING OFF FROM OPA-LOCKS AIRPORT, REDUCING POWER TO CLIMB, THE LT ENGINE BACKFIRED AND THE MANIFOLD PRESSURE SHOWED A SLIGHT DROP. AT THAT TIME THE CAPTAIN DECIDED TO DO A PRECAUTIONARY ENGINE SHUTDOWN AND RETURN TO HOME BASE. THE LT ENGINE RT HAND MAGNETO WAS REPLACED. ENGINE WAS RUN AND FOUND TO BE OPERATING NORMAL IAW MFG SPEC AND THE AC WAS APPROVED FOR RETURN TO SERVICE. (K)