As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED RIGHT ENGINE SURGES, SHUTTERS AND VIBRATES ON ALL POWER SETTINGS. MAINTENANCE INSPECTED AND FOUND CYLINDER NR 4 WEAR IN EXHAUST VALVE KEEPER AREA, AS WELL AS INTAKE AND EXHAUST LIFTERS NOT WORKING PROPERLY. REMOVED AND REPLACED CYLINDER #4 AS WELL AS THE INTAKE AND EXHAUST LIFTERS WITH NO FURTHER DEFECTS NOTED.