Generally speaking, expect to see EPA estimates ranging from around 16 to 20 MPG in city driving and 20 to 25 MPG on the highway. However, real-world fuel economy could be lower, depending on driving habits and vehicle condition.
To get a more precise estimate for a specific car, you'd need to know the engine size (e.g., 305 cubic inch V8, 262 cubic inch V6) and look up the EPA ratings for that particular configuration in a 1986 Chevy Caprice Classic brochure or a reliable automotive resource from that era.
