What was found
(CAN) PILOT REPORTED INTERMITTENT SLIGHT POWER LOSS & ROUGH RUNNING AT CRUISE POWER, GROUND POWER RUNS SHOWED NORMAL. INSPECTION OF RT ENGINE FOUND NR 3 CYLINDER FUEL INJECTOR "LOOSE" IN CYLINDER HOUSING AND FUEL STAINING AROUND THE AREA. FUEL INJECTOR THREADS & CYLINDER THREADS WERE DAMAGED. IT WAS NOTED THE FUEL INJECTOR LINES WERE PROPERLY CLMAPED AS OUTLINED IN AD 93-02-05 (SB 342). INSPECTION OF THE OTHER INJECTORS FOUND NO PROBLEMS. SUSPECT VIBRATION TO HAVE CAUSED THE INJECTOR TO LOOSEN. NO UNUSUAL VIABRATION REPORTED PREVIOUS TO THIS.