turbo 2 sputters from 4k rpm to redline and only makes half the boost
 

it sputters from 4k rpm to redline and instead or making 10psi it makes 5. i tried changing spark plugs and it didnt do anything, it has 750cc secondaries and walbaro 255 fuelpump so i dont think its a fueling issue, they only have 2000 miles on them, anyone know what it could be. car has been running 10psi with no problems for 10k miles so i dont think its anything to do without having a tune

Check for a boost leak. If it idles poorly check for vacuum leaks too.

Improper ECU Grounding issue

The ECU ground is the most important ground relating to the performance of the car. Almost the entire fuel injection system grounds through this point with the exception of the O2 sensor and ignition coils. If this ground is poor, then all manner of weirdness can result including the infamous 3800 RPM hesitation. Because this ground is so difficult to access (it is located under the upper intake) it is often ignored and left to corrode.

research grounding issue and how to properly ground by Aaron Cake via google

I checked the ground , didn't do anything to help, and I don't have a boost leak, any other suggestions

faulty secondary injector wiring/injector clip.

I agree if it happens right at transition and above (3800rpm )then a secondary injector has stopped working, or clogged severely.

Ive had old connectors' pop off before. Inspect them carefully and have both secondary flow tested

What are all the mods to the car? Stock ECU on stock map? Stock induction system?

Check your blow off valve and wastegate for proper sealing.