Sounds like air entering somewhere, and/or the tank strainer might be occluded? On a new to you car, definitely replace all the filters. And fluids, including brake fluid.
22psi? I'd question the accuracy of the gauge. Most stock engines can't make more than 15-18psi peak. Spec is 12psi, +/- a couple of pounds. Extra boost doesn't make power, it just overheats the intake air charge and increases EGT's... not good.
