I know you changed the idle control valve last year but they do get blocked quite easy. Just take it of give it a clean and what i do it get a small screw driver and move the spring inside carefully and spray Wd40 and that lubricates all inside to stop it sticking. Also reset the ecu afterwards if not it will still be the same. Ive had my GTi 2 and half years and ive had to clean mine 3 times.

Changing to 2ltr maf and tb would not make no differene to that.
Hope this helps bud