Help Identifying Part, Please

[87Jetta]

This will show my ignorance, but y'all have helped me in the past and I am stumped.

There is a metal tube-like part next to or attached to the manifold of my 87 Jetta. The part was capped with a rubber tip, but the rubber was old and it crumbled away. I would like to replace the tip, but I do not know what I am looking at/for. I cannot find it in my Chilton's.
Photos available at http://www.geocities.com/stevewebste...-hot-tube.html
(sorry 'bout no hyper link, not finding a way to do it... copy and paste will work)
Is the missing tip the reason the engine sounds much louder now?
Is there something more I should know about this part?
Thanks!!!!
Webster

[87Jetta]

An alternative...
Is there a good blow up diagram / photo with parts identification on the web?

btw, the link does work. It is to our personal page at yahoo where I have uploaded pix of the engine.

thanks,
still hangin'.

[Doug Tatham]

I'm not absolutely sure what it's for. I read once a few years ago, but can't remember. It goes down to the exhaust manifold and I believe it's used to test emissions. I'd find a new rubber cap for it from the dealership. It shouldn't be more than $10.

[87Jetta]

Thank you very much!

[granolasupreme]

Thats the egr tube, its really not very important past emissions.

[veedubmechanic]

if your egr isnt working than you will fail emissions horribly in the NoX reigion.