Boost leak? Boost gauge misreading?

[97gsexx]

However, should air even be able to pass through the valve stem seals on the exhaust valves? I would think that the bad valve stem seals are the only way air could enter the exhaust manifold during a blt. Is this correct? I just don't understand how air could pass through exhaust unless the seals were leaking, thus allowing air pass through the exhaust manifold. I would believe it would make sense if the pcv was allowing air to pass through the vc. If the pcv is not leaking then I have no idea how the air is even getting in the head in the first place. A leaking pcv puts air into the crankcase, not the exhaust. Maybe I just don't fully understand how the valve train works.