2.0t ats p1101

Hey guys, we have an ATS 2.0T with just a cold air intake in the shop, no tune. It is just a short ram style, and the diameter of the maf housing is stepped down to be like stock size.
We are getting a P1101 code, and a rough stalling idle at times. Customer doesn't really want a tune, but wants to keep the Cold Air Intake and obviously not have the CEL or stalling issue.

Has anyone rectified this issue for just that code with tuning for the CAI?

in past i has this code when i installed a maf sensor in wrong direction. its stupidly to ask but did you installed it correctly ? if the maf housing diameter are like stock, there is no reason to have a out of range code. if the maf housing size are not stock you have to recalibrate maf.
also maybe you Intake have a leak after a maf sensor, this will may throw 1101 code.