Thanks timm9, I'll see if I can find a shop with a smoke machine, as soon as I get wheels on my new baby. Actually, what I'd like to do before I do that is disconnect all of the vacuum lines that go external to the engine, so I've just got the motor and it's vacuum lines, no external plumbing. Seems like that would be much easier to debug. Where is the "main" vacuum outlet that feeds the non-motor lines? I'm guessing somewhere on the intake manifold. Sure would be nice if I had a nice anatomically correct picture of the engine and it's various devices labeled. Does that exist anywhere?

I'll go ahead and get a new O2 sensor as well, $25 seems like a bargain compared to what I'm used to paying.

Thanks!