Name That Part!

alright as i was lookin through auctions on ebay for mavericks i noticed this one with its hood open and my 75 mav not having the part circled. Ive always wondered what it was. My mav does have like the mount for it but the rest of it isnt there any ideas on what it is?

 

Air pump for the emissions system.

 

uhhhh .... A/C compressor?

 

yep, it is an air pump, or also called smog pump. Most people took them off as soon as possible if there state allowed.

 

what does it do?

 

Here is a pretty good explanation

http://everything2.com/index.pl?node_id=1459900

 

thanks guys you guys are awesome! =)

 

It kills horsepower and gas mileage in the good name of the EPA (you know alot like an EGR valve)