i own a 99 a3 tq,but i find it difficult to drive it smoothly,it seems to be very jerky when lifting off the throttle. could this be anything to do with the dump valve sticking? has anybody else had the same problem? also,i have just had my 90000 mile inspection,and was told the rear discs and pads would need replacing soon,i am trying to avoid paying dealer prices by doing it myself or taking it to halfords etc,so are there any problems i am likely to encounter with the 4wd system etc? thanks in advance.