[Alpha D]

Your problem awfully sounds like what my car was doing. What me and a friend did to solve most of the problem's was.

-Swap a different maf in (Reason why stock 1g maf was not compatible when i put in the 3g original maf it stopped burning rich and hit boost nicely) Actually driving it allowing the computer to straighten its self out worked miracles to.

-I adjusted my Fast idle control motor screw (Con idle lobe.Mine is close to all the way open)

-Fixed every single boost leak (No matter how small it makes a difference)

-New Filter with the maf

-PCV valve was stuck as well

A Proper Tune Would Definetly help.Yet im sure where ever you take it they will check for all those problems. So i suggest look into those potential problems first. Try and fix all the small things and take it in. It will help you safe money, as well as make things faster. Hope This helps