I stopped by my mechanic's shop today to see what the latest word on the Astro was. He cannot find a reason why the van is hard to start when it has run for a long time. He's run a bunch of tests for vacuum leaks (no more leaks showing up), and he apologizes for not being able to find anything. In a probably unrelated area, he's replacing the tensioning pulley that holds the unibelt in place. I should be able to collect it late Friday afternoon.