Big Pete - it was the over voltage protection relay, which doesn't necessarily compute to idle problems or smooth running, I know. I had been to several indy repair shops who replaced countless plugs, wires, caps, adjusted mixtures, replaced valve seals, etc., nothing of which helped. Finally I found a guy who lives and breathes these cars and he just listened to it for a few minutes each time and then seemed to know where to look. It was an 18 month saga and cost me a lot. Luckily for my panzer, I like it too much to give up on it because of something silly like half a year's pay.