Just wanted to bump this to see if anyone has solved the problem. I've been through the first 58 pages of the site so far, and haven't found the answer. Sid's Toy's post is identical to my buddy's problem. I've also done everything else listed in this thread as far as testing. The problem may be that the engine was rebuilt, and the vacuum lines were screwed up. This is on my buddy's '91 22-re w/AC. I have a access to the Haynes manual (not really a help), and have found several different vacuum diagrams. Unfortunately, none of the vacuum diagrams have all of the vacuum ports that are on the air chamber showing. Anyone have any links to other good resources?
TIA.

Dave