As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, PILOT EXPERIENCED ROUGH RUNNING AND POWER LOSS UPON INSPECTION OF CYLINDERS. FOUND NO COMPRESSION NR 2 CYLINDER. REMOVED CYLINDER, FOUND PISTON HEAD DAMAGED AND EXHAUST VALVE HEAD MISSING. VALVE STEM SEIZED IN GUIDE. SUBMITTER STATED NEEDS BETTER OILING OF VALVE STEM FOR EXHAUST VALVE.