12 valve fuel issue?

Hey working on a buddies 12valve and need some opinions. Is a 97 auto, with stock turbo and boost elbow, has 60lb springs and 4gsk are only mods. It sounds to me like has air in the fuel or a fuel problem of some sort. It doesn't have a miss per say because motor doesn't shake like if you cracked a fuel line but motor sounds almost like its getting air in fuel??? Have a banjo fuel snunber on the way to check fuel pressure but wondering if it sounds like a fuel issue like(overflow valve,fuel heater air leak, injection pump). It has a new lift pump, and there is no visible fuel leaks but It can suck air without leaking fuel right? Lastly, it starts just fine and runs alright but just doesn't sound right to me and he also pulled the fuel plate and it will build about 35psi boost but will not smoke at all even if it's lugged down???? That's mainly why I think it has a fuel problem ... Please help if you have any ideas but I know can't do much till I get some fuel pressure #s. Thanks