This thread might be of some help:
http://ecomodder.com/forum/showthrea...ained-967.html
I agree that a vacuum leak is most likely, but I would recommend you unplug the idle air control valve (located on the front of the intake manifold if I'm not mistaken) and see if your problems go away, it might be malfunctioning and it's easier to rule out than a vacuum leak.
Honda Fast Idle Thermo Valves were notorious for causing this kind of thing, but the VX doesn't have one.