You all know that I've been having idling problems for a while, or you
should anyway, or perhaps you just don't care . . . :^)  Anyhoo, I had
figured out that I had an exhaust leak at the forward gasket in the J
pipe that feeds into the cat.  I figured that I couldn't really diagnose
the O2 sensor till I got that leak fixed.  Today, I took the van into a
reputable exhaust shop here in Cville, VA, to have the gasket replaced.
Unfortunately, they discovered that my muffler had a pretty good sized
hole in it (surprise, surprise).  I'm not too concerned about that; to
my knowledge, the muffler's never been replaced and the van has almost
140K miles on it.  So they're ordering parts and will install them in
about a week.

After having the exhaust checked, I ran some errands, several little
short runs here and there, and by the time I headed back to park the van
and go back to work, my van seemed to be low on power.  I started up the
hill to the parking lot and couldn't seem to get up to 25 mph, so I
punched it to downshift ('87 Westy, auto), and it started losing power
more!  I eased off of the gas and it upshifted and continued
accelerating at a very moderate pace.  When I pulled into the parking
lot and put it in Park, it was idling roughly, at about 600 RPMs.  Seems
to me like it's running very rich once it warms up.  Does this seem to
jive with you all?  I'm hoping that fixing the exhaust will take care of
this, but in the meantime, I may disconnect the O2 sensor to see if that
has any effect.

Another, maybe related issue/question:  What symptoms would you be
likely to see if you had a crack or cracks in the boot between the AFM
and the throttle body?  When I was replacing the oil breather hose, it
looked to me like there might be a crack in that rubber boot . . .

Thanks for any ideas/advice/feedback,
Marc Perdue