Thanks for the reply.
I read your instructions...GREAT! I'm not sure that it's the temperatur though. I probably ought to give you some more info.
Car has been parked for 3 years, so heaven knows what else is going to cause problems. Battery was completely dead - probably for more than 1 year, so I would suspect that any stored info is gone.
The idle issue that is arising appears to be exactly the symptom you described as an OPEN SYSTEM. Idles fast and fine when cold, but as it warms up, it begins a regular cyclic "bounce" between about 12-13 hundred and drops to about 600 or so for a sec then back up.
If I turn the screw on the ICV itself all the way in, the cycle becomes slower, if I open it all the way up, it cycles faster.
During normal driving, the engine appears to work fine (although a bit of a stutter at WOT on acceleration. Most likely, that problem is electrical (plugs, wires, etc.) I haven't bothered to track that down yet because other the the idle fluctuation, the engine runs STRONG. Was rebuilt about 40-50K ago, so I'm going to leave that alone for now I think - it's a minor stutter, not a serious drop in HP.
I'm thinking that the cycling is just too "regular" to be a vacuum leak, and I've blown about 1/2 a can of carb cleaner trying to find one. The initial problem (high idle) was probably due to the tons of carbon in the ICV. I did clean it. Now if I shake it, I get a rattle (like a ball bearing in a can of paint) when I shake it back and forth. Sounds to me like the piston is probably freed up and now working again.
I have changed out the DISGUSTING air cleaner. It had a very weird pattern of dirt on it too. Can't figure out how it happened, but there was a rectangle in the middle of the filter that was entirely black (almost looked like an oil stain). Anyway, breathes a lot better now too. I wonder if the dirty air cleaner was fooling the system......Hmmmm.
Would a dirty MAF sensor cause this? haven't cleaned that yet...
Sorry about the length, but I thought I'd explain as best I could.