A fuel gas gauge replacement for your vehicle is available online from such sources as JC Whitney.com or Amazon.com and even eBay, under auto accessories. To install an aftermarket fuel gas gauge, read the instructions carefully and find the “sender” and “receive” lines, as well as the hot (red) and ground (black) wires. You will find all of this information in the kit instructions from PepBoys or AutoZone; each of which maintains an online parts order desk. There is one huge caveat here and that is you must obtain the correct parts/kit for your vehicle, not just a generic one that covers your 1992 Rolls Canardly. This is so that you will find the right four wires to make this device work correctly.
For more info, see Do It Yourself: Gas Gauge Repair Instructions