this maybe a dumb question but what the heck dose this do it gose down by where my cat would be but theres nothign down there to hook it upto ? can i cap this thing ?

 

It is there to send air to your catalytic converter to help warm it up. If you have no cat you don't need it. You can cap it, but it's not needed.

 

depending if you have a s4/s5 or n/a / t2 ... If you have a T2 (s4 or s5), you can cap it or just take off your airpump, same if you have a S5 n/a... but if you have a s4 n/a, it activates your 5th and 6th ports and you should find a way to hook it on...