I run tru boost. Duty is 45. Spring load is at 4.5

 

Had this issue and replaced the plugs a few times, turns out if your running stock tune it does require them damn expensive plugs to run WOT without sputtering. NGK iridium IX I beleive are what fixes everything. Without boost pills you will only see 12#, get them back in the lines. Search around for location and size.

Edit: I have done a little more research on this issue and fould this on a buick site of all places.
http://www.turbobuick.com/forums/thr...rifice.344019/

The Wastegate hose assembly consists of three vacuum hoses connected by a “T” fitting. It connects the turbocharger compressor housing with both the Wastegate actuator and the Wastegate solenoid. Its function is to route boost to the Wastegate actuator in order to overcome the actuator spring, allowing the wastegate to open, bypassing exhaust gasses around the turbine wheel. This process limits the amount of boost in the intake system to a specified level

Therefore if your pills or missing, the exhaust pressure will control the boost pressure by actuacting the wastegate early vise the solenoid (which will just sit waiting for the pressure so it can start venting off and maintain boost pressure).