89 200 tqa - stalling, and hesitation while accelerating

[Samir Shah <gofast1@home.com>]

Well, past few days have been frustrating - no real progress. After I
cleaned the idle control valve to fix an intermittent wandering idle,
the car now periodically dies when I lift off the throttle! Talk about
making a problem worse. If I lift off the throttle while at speed, the
engine will sometimes drop to around 200 rpm, then bounce back and catch
an idle at 950, other times the car will die around 2k rpm. Of course,
while I'm blipping the throttle while the car is not moving, it never
dies.

If I disconnect the VDO ICV while the car is running, it dies. Ditto if
I disconnect the coolant temp sensor. This normal? 

Also, its hesitating upon partial acceleration, does not seem to make
much power below 4k rpm, then about 4200 rpm, just takes off liked a
raped ape! Not totally sure if power delivery is clean at WOT, but
sometimes it appears so.

No progress on the a/c front either. 

Any ideas? Thinking of ordering a new ICV and coolant temp sensors just
to eliminate some variable. Thanks in advance. Samir.