I'm pretty bad with cars but the cable that goes into the piece circled in blue came off and I realize the piece the cable plugs onto broke off from that piece. I was wondering what the piece is called and how much is it to get it fixed. Is it possible to also just replace it yourself?

 

Here's a better picture.

 

Looking for the name of the cylinder piece that has a hose plugged into it.

 

Take a close up photo.

Appears to be a vacuum switch for the emissions system.