Erratic boost pressure

Two days ago I went out and noticed something weird when I went from part throttle to little more than half throttle... If I laid into the throttle at any speed and any rpm the engine would stumble for a few seconds then pick back up at higher rpm. Shift, rpms would drop and it would do the same thing, would settle down but could still fell it stumbling after staying in it. Went out today and checked for codes and boost levels and leaks...no codes, no obvious leaks but my boost pressure was really erratic. Spiked to 21 then level off to 10-12, but would never be consistant.
Looking through the forums I see that a lot of people refer to the N75 valve could cause boost problems like this. Any ideas?

00 1.8t with K04 and GIAC

Could be.  Have you already upgraded your DV?  I see you are chipped with a K04 - if your DV is stock, that could do it too.

Yes, DV has already been upgraded to Forge 007.

Do the test outlined here:http://www.forgemotorsport.com/media/valve_service(1).pdf
And double check all of your hose connections...