A week or so ago I had weird intermittent missing problems with my inline
ABA motored Vanagon,  which I fixed, with the Lists' help, by changing my
O2 sensor, re-attaching a loose vacuum line and replacing my Temp II
sensor.

  I strongly suspect I had two issues going on...the main one being that
the wiring between the O2 sensor and the Brain was almost worn through.
And the minor longer time ongoing issue I was having with somewhat
irregular 'resume throttle' response, that was most likely the fault of the
disconnected vacuum line over to a warm up flap in the intake.. (I think)

   I've run two tanks of gas through now, mostly highway driving in very
windy conditions.   I've seen almost 3 miles per gallon increase.   I
strongly suspect now that the O2 sensor may have been essentially
inoperative for about a year now...when I did some intake work the last
time, I noticed my gas mileage began to decline to about 21-22mpg but now
it is back to ~25mpg, like it was prior to that old work...My throttle
response is again  clean and predictable, also..

   Love it when I fix a problem and find I have a 'bonus'....