[AKCJ]

ok. It sounds like you've already tested your fuel pressure.
How about getting the injectors rebuilt? I guess they could have some buildup that is restricting flow. I used witchhunter performance for mine.
Pull the plugs and see what they look like.
Check the AFM - does in move freely? is the variable resister swipe worn out?
Is the exhaust plugged?
Check for a vacuum leak - others have rigged up a vacuum cleaner discharge or air hose to pressurize the intake and/or exhaust (carefully).
I'm sure others will chime in.