As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED, DURING CRUISE LEVEL FLIGHT, 658 ENGINE BEGAN TO SURGE +/- 400 RPM. AFTER REDUCING POWER, AIRCRAFT LANDED WITHOUT INCIDENT. MECHANIC FOUND 6 FT PROP GOVERNOR FAILED. MECHANIC CHANGED GOVERNOR AND RELEASED AIRCRAFT BACK TO SERVICE.(K)