What kind of gas mileage does the 1992 Chevrolet caprice classic get?

I feel very qualified to answer this question. Although you did not mention whci engine you have I will assume it is the 305CID (5.0L) engine. My gas milage varied from 17-19 in the city depending on lights and throttle use. On the highway, the Caprice is a truly amazing car. With a wicked overdrive and a lot of weight I got milage as high as 28.5MPG with my Caprice. I accomplished this by drafting quite a bit yet still rolling above 75mph. The Caprice gets it's best highway gas milage at speeds above 75mph on hilly terrain since when you go slower, the transmission will drop out of overdrive which greatly accelerates your fule consumption. I made a pont never to drive much below 80 with my Caprice. Keep in mind that my tires were much upgraded as well as my shocks. If you have standard tires and suspension, don't do that because it is dangerous. I wish I had not sold that car.