I have a similar problem with my 01 SE. But my gas guage seems to operate normal when the car is between 1/4 of a tank and full. One I start reading about 1/4 of a tank or lower my guage tends to read full almost 99% of the time. Every once in a while it will read below 1/4 of a tank upon start up, but it doesn't even take a mile of traveling before the tank starts reading fulll again.

I'm just trying to figure out why whatever the problem is, would only show itself when I'm below 1/4 of a tank. For further clarification, the needle doesn't float around when I'm getting low on fuel, it really just sits at full.

You may have a sending unit going bad.

Here this should help if you replace the sending unit, which from what it sounds like is the problem.
https://www.gmforum.com/mechanical-134/how-change-fuel-pump-fuel-sender-unit-278863/

Thanks for the info, watched the videos and I can't wait to dig in. I'll be sure to post the results after I round up the $40 for the part.

That'* the spirit!!! That would be very helpful if you get back to us with the results. We are always updating our troublshooting database. Thanks again!

Don't forget to buy a gasket (large O ring). Got mine at Rockauto.com. When you remove the lock ring, use a punch or something to hammer on the tabs, and alternate sides. Couple taps on one side, couple taps on the other, etc..... This is the only tricky part of the repair, and it just takes a little patience.