I got it all figured out and reinstalled. Everything is routed properly according to that diagram above. There is a metal line under the manifold that points to the front of the car which is supposed to be hooked up to a hose that routes to the BPT (located at the back of the engine bay). This requires a sharp 180 degree bend with the vacuum hose. I assume that the routing changed in later year cars and they didn't spend the extra time/money to redesign the metal line to point the correct direction...
I've now replaced every vacuum line and cleaned out both IAC valves. It still has a high idle (~1300 rpm when warm, ~1700 cold) and a slight stumble at low rpm when accelerating from a stop. I took it out for a 15 minute drive just now and it got a little better the more I drove. By the time I got back, the idle would bounce from ~800 to ~1300 when in neutral. It's pretty much exactly how it was when I started.
Tomorrow I will pick up a new coolant temp sensor. After that, I'm out of ideas...
