Engine bogging!  I fought this for a year!  I've got an '85 with 
1.9l.  I think the problem was multi-fold  first, there was a  definite 
correlation between bogging and the gas I purchased at one fuel 
vendor.  Switch vendors, bogging would go away or at least lessen.  
The 'bad' gas vendor was selling an ethanol blend, and while I don't 
have hard feelings against ethanol, I try to avoid it when possible 
when I'm driving the van.

Secondly, I replaced my plug wires.  This cured an intermittent real 
rough idle and helped with the bogging problem.  I can't say 
completely eliminated the problem because I've made several changes 
and can't say exactly which cure did the trick.

Thirdly, I replaced my air flow sensor because I was being 
hypochondriacal about the engine performance.  Stupid move.  Don't 
replace your air flow meter unless your van is cutting out at 
specific rpm ranges and then runs smooth at others.  I've become 
something of an air flow meter expert thru my trials and can discuss 
these in another post if desired.

SO:  this would be my prescription for the bogging fix.  It is 
extremely interesting to me that others have had this problem, I 
thought I was an island.
1.)  Replace the plug wires.  NAPA sells an excellent replacement for 
less than dealer OEM cost.  You'll still pay $60-$80 for a set of OEM 
type ones.
2.)  Switch to the 3-prong plugs (see previous post).  They do make a 
difference and are worth the cost IMHO
3.)  Use a non-ethanol fuel.  Apologies to the corn growers and the 
environment.
4.) Clean the engine/computer grounds.  Check the shop manual for all 
the locations but a real critical one is on the top/left side of the 
engine block.  Remove the bolt, scrape the aluminum with a knife till 
shiny, clean the brass eyelets with the brown colored ground wires, 
and I applied an anti-corrosion paste for electrical wire-nut 
connectors.

With these modifications, I HAVE ELIMINATED my dreaded bogging upon 
acceleration syndrome.  I hope this works for anyone else.