THE PILOT WAS IN CRUISE FLIGHT AND SWITCHED FROM THE LEFT TO THE RIGHT FUEL TANK. THE ENGINE SPUTTERED AND QUIT. HE ATTEMPTED A FORCED LANDING TO AN AIRPORT BELOW HIM, AND WHEN HE LOWERED THE LANDING GEAR THE DESCENT RATE INCREASED AND HE CRASHED SHORT OF THE AIRPORT. THE PILOT STATED HE NEVER ATTEMPTED TO SWITCH BACK TO THE LEFT FUEL TANK AFTER THE ENGINE QUIT. EXAMINATION OF THE AIRPLANE AFTER THE ACCIDENT REVEALED THE LEFT FUEL TANK HAD ABOUT 20 GALLONS OF FUEL AND THE RIGHT FUEL TANK WAS EMPTY.