CAR Juice is a term used to describe a type of fuel additive that is added to gasoline to improve its performance. It is typically composed of a blend of chemicals, including detergents, lubricants, and other additives. The GAS solution for the term CAR Juice is a three-letter acronym for gasoline. Gasoline is a petroleum-based fuel that is used in internal combustion engines and is the most widely used fuel in the world.