What sensor/plug is this?

[double0Si]

I was doing my oil change this morning (man am I glad i dont have an 8th gen, this ones bad enough) and I'm finally getting the filter out when I notice this plug dangling above. (see picture)

I checked out my Haynes manual and had no luck finding it. No pics of it on Advance Auto's/Auto Zone's site. It comes off of the harness that runs behind the intake manifold from the firewall near the brake booster. I cant find anything thats missing a plug.

When I replaced the original motor with a OBD1 JDM B16A I didnt retain the Crank Fluctuation Sensor could this be what it was originally ran to?

 

[boostin4fun]

That's what it looks like to me. That crank sensor is a two wire plug and it looks like it would reach to where it is located, so most likely yes. Check the color of the wires and look in your repair manual schematics and you will know for sure.