I need some help.  My van has been hesitating slightly lately and today
(just after filling up with gas), the van would hardly go down the
road.  I'm thinking it might be bad gas (and will add some chevron techron
soon), but its also spitting out black smoke out of the tailpipe.

Now, I thought black smoke meant oil in the combustion chamber, is that
right?

My only other ideas on the hesitation are vacuum leak (but I've looked for
one and haven't been able to find one) and idle switch (the little switch
on the throttle body).  I've checked this switch and it seems ok, but I'll
probably replace it soon just in case.

Any other ideas?
Thanks a ton,
Blake
SLC UT