As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AN INTERMITENT SLIGHT POWER LOSS WAS INITIALY MISDIAGNOSED AS A FAULTY GOVERNOR CONTROL BOX. WHEN THE PROBLEM PERSISTED, IT WAS DETERMINED THAT THE EXHAUST VALVE IN THE NR 1 CYLINDER WAS WORN AND HAD A SMALL PIECE MISSING. THE CYLINDER ASSEMBLY IS CURRENTLY BEING REPLACED. (TC NR 20070904001)