How big is a 1988 dodge ram truck gas tank?

The size of the gas tank in a 1988 Dodge Ram truck varied depending on the model and configuration. There's no single answer. It could range from approximately 19 gallons to 30 gallons. To know for sure, you'd need to check the owner's manual for that specific truck or look at the fuel tank sticker (often located inside the driver's side doorjamb).