This sounds like vanagon syndrome , or imation vanagon syndrome,depending
on the year of your vanagon.  Real VS is supposed to occur with the 2.1
only.Check the archives for vanagon syndrome, and the possible
solutions.Maybe you will see other people with your symptoms. It can the o2
sensor , the ecu, the distributor , the afm,ect,ect ,ect, or, in my case,
the wiring inside the  distributor.Carefully check  all conections again
and again, and inch along the wiring, looking for a break or something
burned through.The plug that goes into the distributor is a suspect also.
The gas smell is probably when you fill the tank. One of the gromets on the
tank has gotten out of position. Follow along the plastic lines from the
expansion tank with your hand, and feel for a loose gromet.I think you can
get a good buzz from this situation in the mean time.Just dont crack the
window when driving.