As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT ENGINE RAN SLIGHTLY ROUGH AT CRUISE ALTITUDE (5,000 FEET). NOTED OIL LEAK AT NR 6 CYLINDER POSITION. FEATHERED LT ENGINE AND RETURNED TO HONOLULU. AFTER LANDING, FOUND NR 6 CYLINDER FAILURE. (METAL PARTICLES (ALUMINUM) FOUND IN OIL SCREEN. REMOVED ENGINE. NO RECOMMENDATIONS FOR THIS PROBLEM.