Hi folks,
    Here's the facts: 88GL 115k miles.  Starts fine, runs well for about 15
minutes and the idle speed starts falling. If I keep trying to run it at
that point, I'm riding the gas to keep it from stalling. Of course, there's
the bucking and power loss, too.
    Salient facts(maybe):
    -Most recent work done- replaced temp sensor for the dash(thanks to all
who gave their advice). Did and up loosing a bunch of coolant through my own
clumsiness, but have replaced it and been slowly bleeding the system. Small
bubble left in the expansion tank.
    -O2 sensor functional, averaging .5 v when connected, and around .8v
steadily when not.
    -If I stop and restart with the engine warm, the idle will be fine for a
few minutes and then start failing again.
    -Timing at normal, V-mark lined up with the crank case joint.
    -New cap and rotor installed today, block and engine bay grounds
recently cleaned or moved where needed. Cables and plugs less than a year
old. Throttle body recently cleaned.
    -I'm not using the Idle stabilizer; when connected the engine revs to
2500 or 3000 and just sits there. I've never used it in this van, and after
wrestling with it for a long time I just disconnected it. A parts cost vs
benefits choice I had to make.

    I've spent most of today trying to figure this out. Double checked and
re-set the timing, replaced a suspect vacuum hose to the fuel regulator,
repeatedly starting from scratch with the idle setting, following bentley
procedures. The idle screw does almost nothing when the RPM's have fallen so
low, it just makes the exhaust smell better or worse.  I'm desperate, this
van is scheduled from some serious driving in about a week.
                            any ideas?
                                    Thanks,
                                Matt Sutton