Well I got the van back from my mechanic today. There seems to have been two problems. Changing the UIM must have solved a vaccuum leak but the bucking/stalling continued. As it turns out there were about 8-10 burnt/broken wires in the loom under the alternator. They have been replaced and all seems well. I will probably punch the cat anyways since I won't have to do an emissions text until 2008 and I likely won't have the van by then. I might as well take advantage of the extra power and gas mileage
I hope this helps others troubleshoot and I wanted to again express my gratitude to those who helped.