I'll do my best to think this through. When my foot comes off the accelerator and my car coasts to a stop at a stop sign, and my switch is disconnected, the rpms will dip to the point where the engine shakes a bit (maybe as low as 600 rpm) and then comes back up to around 900.
When my foot comes off the accelerator pedal and the switch is connected, the idle does not dip, it just stays at 1100.
If your car has the same symptoms as mine does with the switch disconnected, plus an occasional stall, I would say there is a pretty good chance that your switch is FUBAR'D.
To be absolutely sure, disconnect the switch and run around a bit. Its a 20 dollar part, which, for me, falls in to the 'throw parts at the problem' catagory. Also, make sure your throttle linkage is tight, because if it isn't, it may not be pushing the switch down.