Thanks to all for your ideas, comments, and general patience with me on this problem. The new O2 sensor is on order and should be here in a day or two.

Meanwhile, I can use Art's plug technique as I already have the required part (sandwich bag) in stock. I think I will prefer that technique to grounding out the constant idle control since I understand physical blockage better than I do electrical stuff (can you tell?).

And I will re-check the CO setting on the AMM by reading the O2 sensor output with my volt meter rather than the pink wire test point. This will give me a good comparison for when the new unit arrives. I do expect to see voltages bouncing around within the range rather than just sitting steady.

I agree that the FPR could still be the issue in that it is possible it could fail in a manner that still produces higher than standard pressure on the injectors while still allowing fuel to go back to the tank. I say possible because my limited mind cannot quite see how that would happen when the fuel was coming out quite readily in my test. It was not a mere trickle.

It is clear, however, that the AMM alone has made a major change/improvement in my situation and I am glad for that. $100 well spent on my aging friend. All of this has taught me a wealth of information that I have managed, since 1983, to not digest and I appreciate your helping me out.

More later. Thanks