Well I changed my plugs, took the Stang for a quick drive and kept hearing a rattling noise coming from the exhaust. When I got back I saw what appeared to me to be a smog tube just hanging there. Is it possible I could have made it loose and knocked it off when doing my pass side rear plug? I'm going to wait til it cools off to check under there again. I am going to remove all the smog stuff at a later time, but what can I do for now? And where does it hook up to?

Thanks,
Matt