Which is worse, having car trouble on the way to the dentist or getting through the problem and making the appointment on time to have a filling replaced?  Not a typical Monday, but certainly a contender.
Van is an '87 Westy with stock 2.1L WBX and manual trans.
As mentioned, this is the second time in recent weeks this has happened.  First time was on neighborhood surface streets when I noticed the van slowing down from about 25 MPH.  Felt like fuel starvation.  Kept feathering the throttle since I did not want to have it die and not be able to restart.  Revs varied wildly and the tach needle swung from 0 to about 3,000 RPM.  No power when it did rev.  After about 1/2 mile and a minute or so it cleared up and ran normally for the rest of the trip.
Today I was doing about 60 on the interstate and the behavior was nearly identical, compounded by the need to negotiate a cloverleaf ramp.  Once again, it cleared up quickly and did not reoccur on that trip or on the way home.
I plan to change the fuel filter as a precaution but wonder if anyone else has had a similar problem and can advise.  Thanks!
Stephen