Hi I'm new to this forum, as far as posting a new thread anyway. I've been looking through many trying to find some answers / remedies to my problems. I know there have been a lot of posts already about this fault / problem, but recently my 2005 Audi A4 2.0 TDi started to have a loss of power, mainly when in 2nd/3rd gear around 1500-2000 rpm. It also jerked sometimes, but eventually sorted itself out, usually after going past 2000 rpm, and was followed by a puff of black smoke / dirt / dust out of the exhaust. This was initially very intermittent, and usually when running a bit warmer (After about 20 minutes of driving) but gradually got worse, and when running cold (Starting up didn't sound very nice!) After looking at some forums, it sounded like the MAF sensor / filter, so took it to the local dealer, although due to how intermittent it is, i couldn't show them the problem. Funnily enough, the MAF sensor / filter is what they replaced, at a cost of approx. £280 (Plus diagnosis charge and labor). Drove away...still happening. Wasn't very happy, called them back and had a chat / argument with the service manager saying that I'd payed for the fault to be diagnosed, but it wasn't, and he said to bring it in for another look. This time, it was the EGR cooler at a cost of £260 (Part only with 10% discount - They didn't charge me for diagnosis check or labor this time). Drove away....still happening, and this time the 'Emissions Control System' Light had come on. Once again, i called, argued again and they said i had to bring it in ASAP due to the light. This time it was the EGR Valve (what a friend of mine at work said it was/could be to begin with). So another argument, with me saying that i wasn't convinced they would ever repair it due to them failing to do so two times already, plus at a rather large sum of money to me too, and they said they it could of been any of the parts already replaced that went down, and i argued again why i was paying for all three parts when they should have diagnosed the faulty one straight away. Anyway, EGR Valve replaced and i only paid for the part (£240) with the manager guaranteeing me it would work and said that if it didn't work this time, he'll pay for it himself. Drove the car away for the 3rd time, and all seemed great. It drove really well (as it used to) and i was finally happy-ish. Then two days later, pulling away from a roundabout, getting up to 3rd gear, sudden power loss again, lots of jerking to the point the car virtually stopped and nothing would happen. I had to pull over, hazard lights, turn it off and re-start the car and then it was fine again. Another two days later (Approx. 40 miles later), its happened again. No lights have come on or anything, just no power, jerking, stopping, some smoke and the only way to get going again is to restart. I know they said they do it for free, but i'm loathed to go there, only i may not be able to contain my anger and drive the car through their showroom window. But it would be nice to go there with some top tips, possible solutions, and or least some comments from others who have experienced similar problems. Please please please can someone shed some light on what they think the problem could be, and why Audi are so useless to finding out the problem themselves. Any help would be very very much appreciated, thanks.