Yep. You were right. I made a smoke tester out a coffee can, tubing and smoke bombs and found vacuum leaks that I would have sworn didn't exist. Put the car back together, and it runs great.

To make the smoke tester, I just cut a hole in the plastic top of a large metal coffee can and glued tubing to it. I attached the other end of the tubing to a small intake inlet pipe. 'Tossed a lit smoke bomb (small, N.C. legal type) into the can and put the cover on. The expanding gases pushed the smoke though the tubing and out through the leaks. Orange smoke bombs worked great, but use small ones. Even those will pop the top off the can.

Thanks again for the help Klaus.