Well, as I said, my EGR was not clogged. A plastic tie is just one of those things you buy to hold wires and hoses together. It was stiff enough but flexible enough to shove up the passage. It would have loosened the carbon, but there wasn't much.
Anyway, my problem was solved by throwing away the dumb Autolite plugs I had put in and using Motorcraft AWSF 32PP plugs instead.
Why didn't I think of that earlier? Who knows. I change the plugs and get a bad running car. But it can't be the plugs, can it? -- I just put new ones in!
Oh well, we live and learn.
