On August 10, 1997, at 1400 mountain daylight time, a Mooney M20C, N9666M, registered to and operated by the pilot as a 14 CFR Part 91 personal flight, experienced a loss of engine power while in the pattern to the Bountiful, Utah, Skypark Airport. The pilot was unable to land the airplane at the airport and made a forced landing short of the runway. During the landing, the airplane struck a parked tanker truck. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the private pilot received minor injuries. The pilot rated passenger was seriously injured. The flight had originated from Three Forks, Montana, at 0800. A stop was made at Pocatello, Idaho, due to adverse weather. The flight departed from Pocatello approximately one hour prior to the accident. The pilot reported that the flight was uneventful until he entered the downwind leg for runway 16. The pilot stated that while on the downwind leg, the engine started to lose power, stopped, then restarted with a surge, and then stopped again. The pilot reported that he was unable to make it to the runway and tried for an open field. Just before landing, the engine surged again and the airplane struck a parked tanker truck which severed the right wing from the fuselage. The pilot rated passenger reported in a written statement that, when the engine quite then restarted on the downwind leg, the pilot tried unsuccessfully to switch fuel tanks. As the airplane turned onto the base leg, the engine quit again. The pilot turned the airplane to the open field and as the pilot initiated the flare, the engine started again. The passenger stated that the pilot pulled up and banked left toward the runway. At an altitude of approximately 20-30 feet, and still in a steep left turn, the engine quit and the airplane immediately struck the parked tanker truck which severed the right wing from the fuselage. Post crash investigation of the wreckage revealed that the fuel selector was positioned on the right fuel tank. Rescue personnel reported that there was no evidence of fuel spillage or fuel smell in the vicinity of the right wing. The left wing remained intact, and approximately 15 gallons of fuel was later drained from the wing tank. A Federal Aviation Administration Inspector from the Salt Lake City, Utah, Flight Standards District Office, reported that the fuel line to the carburetor was empty of fuel. The carburetor fuel bowl contained less than one tablespoon of fuel. After the wreckage was retrieved and moved to a facility in Spanish Forks, Utah, the engine was prepared for an engine run. Fuel was supplied via the left wing. The fuel pump was activated and the engine was started. The engine started immediately and was run for approximately three minutes. The engine ran smoothly and both fuel and oil pressure gages were indicating in the normal range.