On January 28, 2003, about 1736 eastern standard time, a Mooney M20K, N231NT, operated by a private individual as a Title 14 CFR Part 91 personal flight impacted with the terrain during a forced landing at the Grand Strand Airport, Myrtle Beach, South Carolina. Visual meteorological conditions prevailed. No flight plan was filed. The airplane was substantially damaged. The commercial-rated pilot and one passenger reported minor injuries. The flight was originating at the time of the accident and was en route to Greenville, South Carolina. The flight had departed on runway 23 and the landing gear was retracted. The pilot reported a "loud pop" followed by a loss of engine power. The pilot lowered the landing gear in an attempt to land on the remaining runway. The aircraft came to a stop about 250 feet past the end of the runway and 200 feet left of the centerline. According to the FAA inspector, an examination of the aircraft's engine revealed, that the number 3 cylinder read 3 to 10 psi over 80 psi when a cold compression differential check was performed to the engine. According to the FAA inspector "this was not a cause for the engine failure." In addition, he stated that the fuel, along with the fuel systems, was examined and no abnormalities were found. According to the FAA inspector's statement the pilot stated that part of her preflight was to select the right tank when her husband is on board. The fuel selector was found in the "off" position at the time of the FAA accident investigation. Someone from the fix base operator stated to the FAA, that he assisted the occupants out of the aircraft and turned off all switches. He remembered the auxiliary fuel pump was "on" and the fuel selector was pointing to a position between the left fuel tank and the off position. When asked to put the statement in writing he would not corroborate. The FAA asked the pilot if she attempted to turn the fuel selector to the off position at the time of the accident? The pilot could not remember.