Don't think there is any water in your gas tank do ya?  Changing the filter
was a good idea but if there is water in the tank or alot of junk it may be
plugged again.  It sounds to me like fuel filter problem caused by something
bad in your gas tank.  Has the van ever sat for any length of time?  Or have
you ever got gas at a really cheap gas station?  From the way you helped the
problem you just told yourself where the problem probably lies.  Check out
the gas tank and the filter.  Hope I helped.
Ken Wilford
John 3:16
(609)-327-0027