Pressurized engine

[marek4792]

Not necessarily. The crankcase isn't 100% air tight. To rule out the head you'd have to remove the rocker shafts so all the valves are closed and test. But even then 20 psi boost you'd should hear it pissing air/exhaust somewhere.. Kinda starting to think you may have a sensor in range failure causing low boost and not necessarily a mechanical issue...