TPS Drama! All out of ideas

[Infidel Edition]

So I'm getting around to fixing up the '89 ~ looking at a 2 door a friend has - and I finally believe I know what the random no start issues are caused by.
Mostly because I've thrown at everything else!

Seriously, I've discovered that the TPS doesn't stay set to spec.
I followed 89Lorado's instructions for setting the TPS for a manual.
I get it to the perfect sweet spot...
And as I tighten the screws, it jumps from .83 back to 4.53+
No the tps isn't moving.
I've tweaked and played and as long as I don't tighten it too much it stays at .83

But then, after a short trip (20-30 min), I can cut the engine and it's off again.
My guess is the engine vibration and temp enable it to move???
Don't know, but going crazy.

It's a new ECU and a new TPS. I thoroughly cleaned the throttle body...
Out of ideas