Mine just didnt pull smoothly, now this could be any number of things but in this case it the only possibilty and it was MAF. You can run without it on for a short while and see if it seems more responsive and smooth, if it does then thats probably it. Then re connect. It may then throw up a warning but mine didnt. You can buy these from any number of places, but I went to Audi because one of the major other suppliers have been known to sell copies and I didnt want to muck about. I believe there isnt a specific warning code for the MAF, but someone who knows their diagnostics will be able to read the codes and it will point to this.