My TP returns to the up position. With that said, try pressing on it right after you shut off the engine. Then wait a half hour and try again. I don't remember if having fuel pressure would help it to bounce back into position or not?

So I'm thinking that maybe if there is an internal fuel pressure leak, and no fuel pressure (with car off), then that might cause the plate to not return up? Whereas with fuel pressure, it would return up?

And there might be fuel pressure there right after you shut off the engine, but would drain back into the fuel tank and be no fuel pressure after a period of time.

If this is the case, then we may have found a new method of testing for an internal fuel leak!