The car in question is a 2006 2.0 tdi (140) s line Quattro. On Thursday whilst travelling down the A3 around 70mph I pushed the throttle to move past another car and got no response. Tried harder untill foot was flat but nothing, it would just about hold it's current speed. Tried dropping down to 5th and nada, just slowed with no pick up. Found a layby and had a look under the bonnet and couldn't see anything but if I'm honest I have no idea what I'm looking for anyway. Restarted the car and it seemed ok so set off and it was running fine again. 10 minutes later it did it again. Same thing, pulled over, restarted and it was fine. Car has behaved since....until this evening coming down the m3 when it did the same thing. Can anyone offer any insight into what might be causing this?