CIS-E warm no start

[Chris Cappuccio]

My 89 80q has sometimes dipped a little bit low in RPMs when I go from
open throttle to idle.  Also, on occasion it will be hard to start when
it's warm, it might take 5-8 seconds of cranking before it will fire up.

I cleaned up the ISV....It seems to idle fine most of the time (if it is even
the cause issue), the idle only dips when I go from medium-wide open throttle
to shut...

Recently, the weather has gotten very cold to where days have a high of 15
degrees.  All the sudden, my idle dip and hard starting got WAY worse.

Now, when the car is cold, and I go from open throttle to idle, the engine
will dip too low in RPM and stall unless I hold it for a sec.  If I keep it
at 1000 RPM and then let it idle, it keeps going just fine. 

Worse, the hard-starting when warm is now NO START when warm!  I have to
wait 20 minutes in the cold weather before it will start again.  The car
runs fine before it's stopped, it just won't start back up.  It looks like
a fuel issue (it still sparks, just no start.)

Both of these problems went from minor annoyances (little RPM dip and
hard starting) to major problems (big RPM dip and no start) right after the
weather got colder.  Either they're related or I'm having multiple issues.
So far i'm not finding any big vacuum leaks....any ideas?