1990 All Other Makes

After owning my '90 vette for four years, I've just developed a problem with the gas readout on the dash. Although the tank is full, it shows as empty and in the reserve area. It first happened when the tank was low and it reverted to half full (showing a number of stacked bars on the gage). However, when the gas was being used awhile, it reverted to the reserve indicator on the dash again and has stayed there through several fillups. I tried to pull several fuses that controlled instrument panel stuff and hoped it would reset, without success.
I'm guessing that the gas tank sender might be bad or the gas tank sender screen might need replaced.
Is there any way to determine which, if either, is the culprit? If I have a mechanic drop the tank and inspect the sender and screen, is there a way to determine the culprit, or is one more likely than the other?
I'm trying to determine if I have to spend the $340 or so for the sender, or just the $25 for the screen and the labor involved.

January 16, 2006.

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