Um what about the lambda sensor as this controls idle reason for when you start up your car it isles high and the lambda sensor brings it down doesn't throw up a fault code either

from what your saying that's all it could be, everyone jumps for a new MAF when was the last time u cleaned it? If I had to buy a new maf everytime my old golf got lumpy I would b bankrupt, eBay MAF cleaner it's in a blue bottle from Cardiff enough for at least 50 cleans and works everytime, never failed to cure my lumpy idle and remove fault code from vag com all this for £8 Inc delivery. It's not hard to clean you just spray it dnt touch poke rub just spray and let dry SIMPLES