No, mine reads full all the time except for at startup when it briefly swings down to 3/4 tank. Also rests at 3/4 tank when engine is off with key on Accessory.

Glad you got yours fixed.

Problem Solved
 

I was able to take the information you gave me and perform two tests to finally solve my problem.

First, since I had previously grounded the BLK/WHT wire near the pump/sender unit, the BLK wire at the PCM should also be grounded. It was not(infinite resistance to ground) so this tells me that there is an open(break in that wire).

Second I took a long jumper wire and connected it to the BLK/WHT wire by the pump/sender unit and the other end into the back of the PCM connector. This should bypass the open circuit and reconnect every thing the way it was designed. The gas gauge did work again with this setup.

I have concluded that the connection is probably broken somewhere between the firewall and the back of the engine. As much as I would like to repair that, it is probably not reasonable to start tearing into the wiring any more(if I could even get to it). I think I will just install a permanent jumper and secure it along the wire bundle. If I solder and heat shrink the connections it should be just as good as it was originally.

swartlkk, Thank you! I could not have solved this without your help because it is impossible to figure out where something is supposed to be connected when it is disconnected.



UPDATE: While preparing to run the jumper to permanently fix the open wire I found the break. It was actually in a very accessible location on the connector at the rear of the transmission under the car. It looks like they forgot to disconnect this before pulling the engine and it pulled the wire out of the back of the connector. To fix it I just cut the wire going into the other side of the connector, solder and heatshrinked it all up and as good as new. Wish I saw that wire pulled out of the connector much sooner. Oh well at least it works again.