93 Z28...I've never really dealt with fuel system issues, so this is all new to me.

When I fill the tank, the gauge reads way past full. No matter how far I drive, it will only drop as low as just-below-half. If these things have a float in the tank, seems like it's stuck way up there, because the tank never shows near empty.

Thoughts on what might need fixed or replaced?

 

Gas gauge (float activated) is screwed up due to the triangular shape of the tank.

Shoebox explains it:

4th Gen LT1 F-body Tech Articles

 

Looks like I get to spend more quality time under the car with a multi-meter.

This will be my 5th 4th Gen...it's definitely the oldest I've ever had, since owning 4th gens since the late 90's. I do remember the v-shaped tanks and rapid drop from half-to-empty, and taking forever for the gauge to come off "full". This is different, though, with the tank physically empty it still reads just less than half a tank.

I'm guessing the sending unit is messed up, according to Shoebox's writeup. That'll have to wait to get fixed, just a nuisance for now, I guess. The fuel pump is still good.

 

My '94 gas gauge has been screwed up since I bought it in '97, and I got my gauge cluster rebuilt in 2017 and it's still not right.

I just always go by the trip odometer. Every time it hits 140 miles I fill it up.