[PowerHaus944Turbo]

I have a 1987 944 Turbo which has been fitted with an Autothority mass-airflow sensor, K-27 Turbo, and upgraded DME software. The car idles properly, but at mid throttle / high rpms it begins to sputter, horribly. At full throttle, the car accelerates fairly smoothly, albeit at a very fast pace. The only progress that I have made has been to adjust the mixture to be richer with the idle screw on the throttle body and the in-line set screw on the Autothority harness (though this only has produced marginal results which vary with temperature). Could it be the throttle switch? Does anyone know the proper pins to check? (The Hayne's manual indicates pin 12, and there are only 6.) Could it be my mass-airflow sensor? (I hope not.) Any help would be greatly appreciated.