There are cars powered with around 300 bar compressed air (around 4000 psi), stepped down to around 500 psi, with a range of 50 - 100 miles.
Reading about early torpedos, it was found that heating the air released from the storage cylinder would increase its propelling efficiency by increasing its pressure, or volume at a given pressure. These were called "dry heaters".
Additional expansion was gained by adding water to the heated air to create steam, which also served to control temperature levels in the combustion chamber. These were called "wet heaters".
Increasing volume at a given pressure is ... a jet engine! In this case, the air is already compressed, and the exhaust drives a piston, instead of a turbine (to extract mechanical energy).
According to Gas Law, pressure and volume are proportional to temperature (kelvin). Water to steam is around 1 to 1600 expansion in volume. Heat could be more fully utilized instead of wasted as in an internal combustion engine.
Would a "heater" be a viable improvement$^1$ to a compressed air vehicle?
$^1$ see SAAB Ranotor reference