look under the VX for signs of leaking, you will have to be quick though as gas evaporates quickly.
i would be inclined to guess that its your fuel pressure regulator going bad. i had problems starting when mine went, on a warm start, i would get either a very very high idle or a very low idle and stalling. occasionally coming to a stop, especially on a hill, the vehicle would stall as well
replacing my fuel filter and fuel pressure regulator eliminated these problems completely.