I have had the same problem with the guage in my 92 Pearlie, every since I bought it. I posted a thread about it and had numerous replys.
Beav suggested pulling the sending unit, checking current with a meter etc.... did this, saw the problem and tried a fix to no avail...
I have since bought the sending unit and the slave unit from Stephen in Oregon. His worked before the demise of his car. I recieved an email from him yesterday and I should recieve the parts tomorrow or Thursday. I will post when I install the parts and we will see if this corrects the problem....
Wandering fuel guage and drooping visors really aggravate the %$(* out of me!