As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED RIGHT ENGINE MAP FLUCTUATED IN FLIGHT. MAINTENANCE INSPECTED AND FOUND TURBOCHARGER IMPELLER HARD TO MOVE AS WELL AS LOW COMPRESSION ON THE NUMBER 4 & 6 CYLINDERS. TURBO AND CYLINDERS WERE REPLACED AND THE AIRCRAFT WAS RELEASED TO SERVICE.