Chevrolet 2004 Corvette Owner's Manual page 250

If your fuel filler door release will not operate, there is a
manual release tab. The tab is located against the
upper trim on the driver's side in the rear compartment.
Pull the tab to manually release the fuel filler door.
5-8
While refueling, rest the tether across the tab on the
fuel filler door to prevent damage to your vehicle's finish.
To remove the fuel cap, turn it slowly to the left
(counterclockwise). The fuel cap has a spring in it;
if you let go of the cap too soon, it will spring back
to the right.