I used a spray bottle with soapy water this time and found a couple leaks. Two at the fuel injector bungs (I didn't use a sealant between the bungs and manifold when I replaced them), one at the turbo outlet and one at the inlet (which isn't normally under boost.) The leaks at the turbo outlet and inlet are coming from between the edge of the hose and the pipe, not from a hole or something like that. All very small though, I highly doubt they could be causing a loss of 5psi. I'll pop the hoses off, clean them, and give them a good tightening. May also go rent a compression checker today for the hell of it.