How do I fix this VehicleSeat BodyForce script?

What I'm trying to do is that if the player decides to move foward (throttle) then the seat will move with BodyVelocity. However it stays in place. It is not anchored.

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