Hmmm, I don't know of any direct association between the ICV and the O2 sensor, unless the cleaning of the valve somehow led to readings that pushed the O2 sensor over the (approaching) edge (how's that for a technical explanation?). I recently had to have my sensor replaced when the car failed emissions inspection, and really hadn't been running all that smoothly either, e.g. hesitation upon moving from start, other stuff. For some reason, no check light came on telling me that the thing had failed. Replacing the sensor took care of that, as well as getting me past a re-inspection no sweat.
I also have a '95, and the sensor is located in a bear of a position, atop the converter, at a weird angle making access practically impossible. There is a special ratchet attachment that you can borrow from Auto Zone that'll do the trick (or you can buy), but even at that it certainly helps to have the added leverage of putting the car up on a lift.
O2 sensors last about 80,000-100,000 miles I think, if things haven't been abused (overly rich mixture being one culprit), so if yours is in that range it seems like time for replacement.
Have you checked hoses for vacuum leaks? Something like that may have something to do with the vacillating idle, and in getting at the ICV you may have wrestled with a few hoses that were on the brink.
Wish I could help more, but as they say, a little knowledge...