Very interesting thing happened driving home from work yesterday.  My
van has been hunting (change in idle speed) at idle for a while now and
I have not had time to address it.  I also have a manual radiator fan
switch to use in traffic or when I climb the Cajon pass (6 degree grade)
when the temperature is well over 100 degrees.  I never noticed before
when the van can be hunting and as soon as I turned on the radiator fan,
the hunting stopped and didn't not come back until the fan was turned
off.  The fan draws a fair amount of current in the high setting and I
am guessing that it changes the load on the engine just enough to
correct the hunting problem.  Doesn't tell me which way to adjust the
AFM dial or screw but it does tell me that the overall AFM setting is
not correct for idle.  I welcome comments.

William