I posted a couple of weeks ago to describe a problem with low idle speed when restarting a warmed up engine. Thanks again for all the feedback. I think the problem has been resolved. Here's what I found.

Long ago and far away I installed a variable resistor in the coolant temp sensor circuit to richen up the mixture when restarting a warm engine. All worked fine until recently. Recently I had the injectors serviced. Independently, I found that the resistor reads about 100 ohms in the off position, disconnected from remainder of the circuit. Not a problem when starting a cold engine but thats a considerable additional resistance in a warm engine. Using the resistor was compensating for sub standard injector operation and the resistor was adding its own resistance probably causing excess gas to be injected and sooty plugs until the car got underway.

The installed distributor had a very narrow range for advance. From about 20 BTDC to 30 BTDC. Installed a cleaned up replacement. Readings now go from 12 BTDC to about 38 BTDC at about 2000 RPM.

Cleaned up plugs, replaced points and condensor and checked all ignition wires. All OK. Now hopefully it will stay that way.