My '89 b2200 does something kind of like this. The only way I really get it moving is to adjust the idle speed 1.5+ rpms. If it's any lower than that I stall out at every stop unless I tap the gas a few times. But it always starts right up.
Did you ever figure anything out?
Check the EGR valve, on right side of engine/intake manifold. If the EGR is stuck open or partially open, the symptoms match yours.