On August 16, 1998, about 1510 eastern daylight time, a Mooney M-20F, N6411Q, registered to a private owner, operating as a 14 CFR Part 91 personal flight, experienced a total loss of engine power in cruise flight in the vicinity of Rockhill, South Carolina. The pilot crashed during a forced landing. Visual meteorological conditions prevailed and no flight plan was filed. The airplane sustained substantial damage. The private pilot and one passenger reported no injuries. The flight originated from Dekalb-Peachtree Airport, Atlanta, Georgia, about 1 hour 25 minutes before the accident. The pilot stated he initially departed from Asheville, North Carolina, (AVL) with 20 gallons of fuel in the left and right fuel tank. He flew to Monroe, North Carolina, (EQY) and Atlanta, Georgia, (PDK). No fuel was added to the airplane. He departed PDK enroute to EQY. He was in cruise flight when he experienced a total loss of engine power. He was on the left fuel tank which indicated about 1/8 tank of fuel. He switched the fuel tank to the right fuel tank which indicated about 1/4 tank of fuel and initiated a climb. The engine ran about 4 to 5 minutes before the engine quit. He switched the fuel tank back to the left fuel tank with negative results. He made a forced landing to a soybean field, and collided with an embankment on landing rollout. Examination of the airplane revealed that both fuel tanks were empty. The fuel lines and systems were checked for evidence of leakage or defects, and none was detected. The surrounding area was checked for leakage and none was found. Fuel was added to the left and right fuel tanks. The engine was started and developed power. (For additional information see FAA inspector statement).