I've searched the forums and haven't found a problem quite like mine, so I'll throw this out there.
I've got a 1992 SSE, no mods, and I'm having problems at idle. The RPM'* will cycle up and down from roughly 900 down to around 600. However, the problem isn't consistent. It will idle pretty smooth sometimes, and others it will start the cycling again. Occasionally, usually while driving slowly (ie, parking lots, intersections, etc) it will die completely. I've got no ideas on what may be causing it. My bonnie has 180,000 miles on it, and as far as I know, everything is original except the water pump. Does anyone have any ideas?