I've been driving my '87 a lot for the last couple of days....left
Colorado and now I'm on the road in Indiana.  It's being doing well, but
after driving about 450 miles yesterday, I bought some fuel, put some air
in the tires and continued for about another 150 miles.  during this last
stretch, I experienced little burps most of the way....sometimes a few
within one minute, and sometimes a few minutes between burps.  The one
things that distinguished my last stop prior to the burping is that I
didn't let the engine rest for very long, i.e. it didn't get a chance to
cool off.  Often, when I make other gas stops every 250 miles or so, I sit
around for 15 minutes.  I don't know if this is relevant.  I also went to
a gas station that didn't seem to be getting much business, and I've had
problems with old gas in another car before causing the same symptoms. 
I've heard about wiring harnesses fixing burping, but what are things can 
I check while on the road?  I haven't driven it since last night, and the 
problem might be gone, but I wouldnt' mind checking what I can for now.  
Is there a way to tell if the magic harness has been installed on mine?  
Here's some more info just to confuse matters.  Two days ago in Omaha, 
NE, I put in a bottle of techron, but it ran fine after that for those 
first 450 miles.  Also, since I've owned my '87, I've been confused by 
the fuel filter.  I don't have the big cylinder filter, but I do have one 
of those small plastic rectangular filters.  My understanding is that the 
vanagons came with 2 filters initially, and the second one I mentioned 
was supposed to have been removed at some point leaving only the big 
metal cylindrical filter.  Unless I'm looking in the wrong place, I can't 
find that one.  I'm gonna try and drive to MD tomorrow, so I'll see if 
the burping persists, but any thoughts or advice would be appreciated as 
always.    Thanks  -david