[Fred E]

I'm going to guess that it's throttle body related as I just replaced my throttle body with the Grams throttle body and am having literally the same issue and haven't figured it out yet. My car is also turbocharged on Ecutek. I've just been dealing with it for the last several days and haven't had time to take a look. The throttle body swap was the only change that was made to my setup. My issue could be related to the increased flow entering the manifold, but it's unlikely that yours is the same unless your throttle body was insanely dirty.

I'm not sure that it's related to your dirty air filter as that is pre-MAF. The increased airflow through the clean filter should be detected by the MAF sensor and the car should behave correctly.