I was wondering if that was the case, but I sealed everything up really carefully and used quite a bit of RTV/sealant when installing the intercooler core, and then the blower.. Not saying it isn't possible, but I just would be surprised I guess. maybe I can spray something around the plates to see if I see any air/bubbles leaking.

Would the valve cover breather by itself (as the only vacuum leak) need that much MAF tweaking to offset it???