C-FNVS, a privately operated Piper PA-28-160 aircraft, was on a VFR flight plan from Wetaskiwin Regional, AB (CEX3) to Bonnyville, AB (CYBF). While in cruise flight in the vicinity of Hay Lakes, AB (12 nm NW of Camrose, CEQ3), the engine (Avco Lycoming O-320-B2B) lost a significant amount of power. The pilot attempted to regain power by selecting a different fuel tank, selecting different magnetos, applying carb heat and adjusting the mixture, however none of these efforts were effective. The pilot performed a precautionary landing with partial power on secondary Highway 617, just East of Hay Lakes, AB. There was no damage to the aircraft or injuries to the pilot who was the lone occupant.
A maintenance examination determined that the number 3 cylinder exhaust valve had failed.