[DonRotolo]

Not really, because it is the change of pressure from ~60 PSI to zero that does the work. You are storing mechanical energy as air pressure, and to use it you have to, er, use it (release the pressure).

If you keep 'all' the pressure, the piston in the cylinder won't move (what's going to push it?)

If you keep 'some'of the pressure, it's the same as turning down the regulator to a lower pressure.

You CAN conserve air by using lower pressure - the lowest pressure that gets the job done will use the least air. Additionally, use the smallest volume (cylinder diameter, stroke length) since that saves air, too.

Don