In first gear it will hit 5 psi and stay there till about 5500 or 6000 rpms then jumps to 10 psi. My mods are a pfc, downpipe, and midpipe. But it was doing this before i put all of that on.

 

I can't think of anything specific to check. It may be that your primary turbo is bad. It would be nice if it was just a vacuum hose popped off or a solenoid or something. This place will help you figure out what it could be (if it's not the turbo itself)

http://www.autosportracetech.com/RX-7/rx7stuff.htm

oh, and let us know what the boost pattern is in 3rd gear too.