Well, the reason I thought it *might* be the ECU is that I have had the one in my 71 142E go bad. No joke. Alas, it isn't so simple. Havn't checked fuel pressure yet, will today. Checked the wires to the FI enging temp sensor again. They're still ok, and I tried two other sensors as well. Checked all the grounding too. Could verywell be the fuel pressure regulator. I've already replaced the fuel pump relay, as that conked out on the side of the road a month or two ago.
I've looked at dozens of those little FI trigger contacts. No wear was apparant. And besides, that wouldn't account for a sudden change in engine operation, as I know from ignition points wearing down. It'll get worse for a while before it becomes non functional.
Oh yeah, the engine will run without the throttle position switch. I had a few wires break on the one on my race car. The only thing I noticed was a little more backfiring than normal when I let off the throttle. :)
Yesterday, I did pull the plug wires one by one, and it seemed that No. 4 cylinder wasn't doing much of anything. All the injector spray patterns look ok, so its on to fuel pressure now. At the moment, the engine is missing badly, when I can get it to run at all.

-Nick