Jim-
The only thing the "highly recommended" shop could find was a slight vacuum leak around the TBI bushings. When they richen the TBI with propane the engine smoothes out and vacuum inreases to 18 inches from 15 (after replacing bushings), so there appears to be another vacuum leak elsewhere. It still is hesitant and idles rough, but it sure takes off when you put your foot into it. The engine only has 100 miles on it, so I think I will put some more miles on it to let everything "break in". I'm not getting any codes, so I suppose that's a good sign. Let me know if you have any suggestions.
Thanks-
Tim