Incident
During a cross-country flight, the right engine began to run rough. The pilot feathered the propeller and turned toward the airport to land. En route, the left engine also began to run rough. Unable to reach the airport, the pilot performed a forced landing on a road. During the landing roll, the airplane struck an abandoned car and subsequently collided with the terrain.
Findings
Inspection of the engines revealed that the fuel lines to both engines were partially blocked by an unknown substance.
Background
The pilot reported that in the months prior to the incident, the left engine had lost power at least four or five times. After each occurrence, a mechanic inspected the engine. The problems identified ranged from a clogged oil separator to low fuel pressure, which was corrected by replacing various hoses.