What part is this?
 

Good morning

I have a 2000 ranger 2.5L and have a p0401 code. I can not find this part located in the picture below. Is this the DPFE sensor? The top of the part has what appears to be a round knob that just turns and turns.
I can not locate that particular part anywhere..

https://cimg9.ibsrv.net/gimg/www.ran...68fbae21d4.jpg