Again, thanks for all the feedback. I've been chasing this for months now and it is seeming to get worse.

Imagine this:

At the end of the work day yesterday (Wed) I started her and she ran like junk. In my nice clothes, I decided to have a peek under the hood and try to pull the temp sensor that goes the air intake horn (made no diff) and then the plug off the cold start valve (also no diff.) I saw the alternator plug hanging at an angle so I re-seated it - the center brown ground wire fell out of the connector. OK, so that had fatigued to the failure point! Perhaps that will have something to do with my jumping tach readings (maybe not...) So I looked further while she is warming up...

Yep, I looked at the thick wire lume that passes thru the firewall from the ECU into the engine compt.

Are you guessing correctly yet??

Yes, the metal standoff fitting that the lume sits in as it passes over the aft end of the right-hand valve cover has NO RUBBER pad or any insulation bewteen the metal edge and the single layer of electrical tape that encircles the lume. I didn't want to disturb it any more than necessary because I wanted to drive home still! But I moved it off the metal stand-off and the engine started to change idle speed and roughened then smoothed out and back an forth for a few moments.

I didn't dig in there yet since I got home late (and took my truck to work today,) but I know some of those wires on the underside of the lume had to be shorted together (or cut completely) by that metal rest. Tonight I'll invesigate and maybe take picture or two for your enjoyment.

Maybe this is not the source of every odd behavior by my car, but has to contribute to a lot of it. LOL

Finally, I've found something wrong!!! Now I have to track it all down and repair it. I'll still be following everyone's advice to check the trigger points, timing, sensors and the never-ending search for vacuum leaks.

More tomorrow.
Scott