IMHO, you
must get a GM DEALER service manual to work on the engine.
The huge two volume set often costs a "massive" ~$40 on ebay.
IMHO, otherwise, you're just asking to screw things up, or to take a very long time trying to figure out how to repair/replace something.
BTW, for a 2000+, you want a 2000+ service manual since the 98 and 99 don't have the AIR systems. Otherwise, there's not a huge difference in the 2000+ years.
Hmm, right now, there are plenty of cheap 98 and 99 DEALER service manuals. But, I don't see a 2000+ DEALER service manual for under $100.
IMHO, that's still a STEAL considering the orig price and it's worth. But, the used DEALER manuals often come up for much cheaper.
Ebay search link:
http://www.ebay.com/sch/i.html?_nkw=Intrigue+manual+(2000,00,01,02,2001,2002)
If you're asking about the AIR valves, they are #1 and #17 in the following diagrams:
You can see what an AIR valve, and the the AIR tube, looks like on the engine in the picture below:
My picture is showing what the diagrams above refer to as #1, #4, and #10.
Good Luck!