Hi everyone! Haven't been on for nearly 7 years but I am now the proud owner of a 57-plate 1.9TDi Ambiente. Lovely car, used to be my demo when I worked at a dealer in Kent (!) and I have no complaints. Well, except one. Under light acceleration sometimes she hesitates or misses a bit. Anyone got any ideas?? I'm thinking EGR valve or air mass meter. Not really sure......

at random times, or more often when going downhill?

Are you sure its not just soft throttle response or a bit of turbo lag as most VAG TDis suffer a bit of both and is quite normal.

To eliminate the egr valve just remove the vacuum pipe and plug the end. if it fixes the problem its the egr valve. QED.