I personally cant see the ITG being at fault. Maybe the map hasnt got enough adaptability in it to accommodate the extra flow of air. My car with the bluefin map and ITG wasnt the best either.
I had the prototype vRS ITG intake fitted to mine but with a bigger filter at ITG HQ by Andy. The car was running Bluefin stage 2 at the time. The car didnt run right whilst the ECU was adjusting itself, it was really on/off in its power delivery like it was over/underfueling repeatedly. It got better over about 50miles.
This was later changed to Shark software which i had in stage 1, 2 and 2+ guises and there were no such issues with power delivery.
Before i sold up i reverted the car back to stage 1 shark performance map with ITG. Randomly i was given a Pipercross venom intake by another forum member. I logged the Stock v Pipercross v ITG one after another that day and found the Pipercross actually was more restrictive than the stock intake, whilst the ITG gained 18g/s iirc over the stock intake.
I think RTEC need to have a look at it tbh. The filter flows enough air for guys running stage 2+ on K04 TFSIs, so its not likely that it would struggle on a stage 1 K03.
Sy