Abstract: A combination gas cap and digital tire pressure gauge with a hollow bodied gas cap, a liquid crystal display showing through an opening in the top of the gas cap, a printed circuit board and support electronics located within the gas cap, a battery and battery door, a pressure transducer, and a push button and associated delay circuit to allow pressure reading to remain readable for ten seconds. The hollow bodied gas cap has a removable threaded portion at its lower end. The threaded portion is designed to mate with standard female threads of vehicle gas inlets. An alternate embodiment includes wherein a bayonet type locking portion that is substituted for the threaded portion.