How do I fix this vehicle bodyforce throttle error?

The vehicle won't move. It is not anchored. It is supposed to move by bodyforce.

while true do
    if script.Parent.VehicleSeat.Throttle == 1 then

        script.Parent.BodyForce.Force = Vector3.new(10,0,0)

        else if script.Parent.VehicleSeat.Throttle == 0 then

        script.Parent.BodyForce.Force = Vector3.new(0,0,0)
        end
        end
        end