The fix was common sense. The IACV can only do so much and will not be able to control the idle if the throttle body (TB) plate is open too much, which was my problem. Evidently, some previous owner had, instead of cleaning the dirty TB, cranked up the throttle plate stop screw to increase the idle RPM. So, when I cleaned the TB, the RPM jumped to about 1500 when the engine was warm since there was not a bunch of crud to block the air flow.
I adjusted the plate stop so the brass plate was closed but not touching the casting sides and re-adjusted the microswitch per the FAQS.
Idle is now a steady 750 RPM.
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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