I was just changing the o2 sensor and I found out that this ring (located near the o2 sensor connector) is not connected to anything. where does it connect to? Is it suppose to be this way? btw, I bought the car 3 months ago and it's all stock.

 

It kind of looks like the grounding ring that goes on the back of the UIM

 

Yes, it connects to the UIM on the engine host hook area.

 

I believe, stock, that ring is supposed to go around the rear stud of the upper intake manifold to lower. Put the intake manifold on, then put the ring around that stud, put the nut on, and tighten down as normal.

There is also a ground wire coming off the engine hanger loop on the back of the intake manifold that connects to the firewall with a quick-disconnect.

Dale