What is it?
 

Pulling the engine from an '83 240D. there is a gizmo located sort of above the power steering pump and between the pump and the valve cover (also right behind the secondary fuel filter). There is an electrical cable running from it. I have no idea what it is/does. It also has a lever on the side that is actuated by the throttle. I've seen some engines devoid of this thing. What would it be??. Thanks

Found it. It's a cruise control module.