Well, now I’m getting frustrated. Tonight I pulled the sending unit from the tank; clean as a whistle. Re-installed. Traced every inch of the fuel line (1/2” hardline). Found one area right in front of the tank when the E-brake cable had been rubbing on it. It didnt look worn through, and I saw no sign of fuel leakage, but figured a small hole, especially up above the fuel level which this was, and behind the elec. pump (no pressure) might suck air and not leak fuel (???... anything’s possible). So I JB welded it then wrapped in tape, hoping I found something. Started the car... still the gauge flitters like a humming bird and does not seem to change when I adjust the regulator.

I didn’t get the chance yet to bypass the regulator as Dwayne has suggested, but it’s notable that it was doing this before I added the regulator. I’m beginning to think the gauge is simply bad and maybe I never had a fuel related issue to begin with??? Ugghh. I’ll see if one of my buddies has an extra guage I can borrow to see what it says.

Any further help still appreciated.