I've had this issue since I've owned the car and just assumed it was a boost leak since the previous owner did a hack job with the intercooler piping. Well I've replaced the intercooler piping with a set that's actually made for the car. I can feel it pick-up a little better, but I'm still unable to boost above 5psi. The car acts like it's hitting a fuel cut, it has a horrible misfire and won't pull through it. I can rev to redline but as soon as I get right around 5psi it just hits this wall. I haven't been able to get over 1/2 throttle without it doing this.

I've double checked my vacuum lines since those were also messed up when I purchased the car. I've been looking into getting rid of them, but haven't found the answers I'm looking for about that yet...

Where do I start? I hate this problem!
Here's a picture of my engine bay, maybe you can notice a big problem that I've looked over.

 

I have seen plug wires cause this... sometimes a little maintenance is all a car needs.
and recirculating the bov might help the car run better in general.

 

do u have a data logger?

 

How long have u owned the car? I would also check your boost solenoid and your tune! Data logger would be Key, but sounds like a blown Turbo, is the car smoking when you go into boost?

 

also check the wastgate actuator it might have come off if you have an internal WG, happened to my friend in his car i fixed it with a paperclip temporarily

 

what do your plugs look like?

 

^+1...

When I hooked my wideband up incorrectly (wideband 5v output to ECU narrowband 1v input) the AFR would peg out on the rich side of the gauge and the car would sputter/bog like mad as soon as it built any boost, but I could get it to rev with light throttle/no boost like you say.

 

man i had like the same problem...change your spark plugs first, thats all i needed. I did the wires first and problem stopped for a week...the plugs have been in for over a month andd car still pulls.

 

you said you redid your vacuum lines?? I looked at the engine bay pic and noticed some of them to the intake are disconnected. But if you fixed that, i would say possible boost leak, but you wouldnt be able to redline if it was that, and i would def replace your plugs

 

Check plugs, replace if needed, and Boost leak test the system. Any check engine lights?