Has anyone experienced this rarity? I've got a 53 plate A4 avant 1.9tdi quattro sport and it has developed a erratic mis-fire. I say developed, I have only owned the car for 9 months and has done it on and off since I got it. It will very occasionaly blip at 1800 rpm mainly in fourth gear, although it did do it in third once going down through the gears taking a services stop off the motorway. it has been into the stealers for two weeks whilst I was on holiday so their guy's could drive it to and fro but they said it behaved fine. Plus they ran it out of fuel and didn't want to replace any tight b@stards!! They have listed this as an ongoing fault so when the warranty runs out and if this matter gets worse I hopefully have some recourse?? I would appreciate any input thanks in advance.