As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THE PILOTS REPORTED THAT THE RT ENGINE WAS RUNNING ROUGH IN CRUISE FLIGHT. MAINTENANCE FOUND THAT THE RT ENGINE FORWARD MUFFLER TAILPIPE WAS ALMOST COMPLETELY BLOCKED WITH THE INTERNAL PIPE JAMMED INTO IT. A NEW MUFFLER WAS INSTALLED. THE INTERNAL FAILURE OF THE MUFFLER HAS BEEN DOCUMENTED ON SEVERAL SDR`S.