As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, ENGINE BEGAN TO RUN ROUGH. PILOT POWERED BACK AND MADE PRECAUTIONARY LANDING. INSPECTION REVEALED FAILURE OF THE VALVE STEM ON NR 2 CYLINDER INTAKE VALVE. THE FRACTURE IS LOCATED APPROXIMATELY .6250 INCH FROM THE TOP OF THE VALVE STEM NEAR THE VALVE KEEPERS. SOME WEAR WAS DETECTED AT THE VALVE GUIDE. (X)