Thanks Jeff. Here's some info you may not remember you helped me with a year ago:
1. The instrument cluster is brand new. I had to buy one because one of the digital numbers on the speedo was out (far right one) and it bugged me so much I had to do it. The fuel gauge indicator acted the same on the original cluster as with this one, so I do not believe it's the cluster.
2. From the link below from a technical article on Pelican parts, I thought it was five bolts, not a special tool as you have pictured for the 1997. I'm not arguing with you by any means (You're the expert, not me!) but I wonder if I should just take a look anyway. This guy took out his sending unit, cleaned it up a bit and put it back in...
http://www.pelicanparts.com/techarticles/911_fuel_tank_sender_replace/911_fuel_tank_sender_replace.htm
Thoughts? Comments?