Student pilot flying experimental aircraft reported engine power loss on final approach. Conducted off airport landing without incident.

Narrative

On final approach to ZZZ in perfect VFR conditions landing Runway XX; my aircraft experienced power loss. I had just completed two S turns for spacing (authorized by ATC) and after leveling for short final the engine started to sputter. I had 8 gallons of fuel on board. I was 800 feet AGL and 0.25 miles from the runway. I realized I was not going to clear the airport fence and immediately diverted to an adjacent concrete culvert adjacent to the airport. The engine stopped prior to my landing. I touched down on the mains at 66 knots. No damage to the aircraft or property occurred. No individuals or myself were harmed. I was flying solo. I experienced loss of power likely due to fuel starvation NOT exhaustion. There is a possible issue with the fuel valve selector that may have contributed to air getting into the fuel lines. The S turns on final may have also contributed to fuel sloshing around in the tanks and air being drawn into the system. I plan on changing the fuel valve selector and avoid S turns on final in the future.