I've had my 2006 A4 DTM for over two years now. When I first got the car it was treated to a new Cam chain and oil pick up for the revised item as a preventative measure. Since then there has no expense spared on the car, it has been regularly serviced with Mobile 1 oil and Genuine filters. I also use the car for my daily commute to and from work (around 12 miles round trip) giving it good runs on journeys back to see my dad in Birmingham. Performance has been great (especially as it's a stage 1 Revo) and has been faultless until recently. A Month ago I was returning from work and put the hammer down, the car surged forward till it got to 3500rpm and then it cut out. I tried it again and the same thing happened. I drove the car slowly and gingerly let the revs rise and they managed to get over 3500rpm and towards 5500rpm without any issues. I plugged in VCDS and monitored a number of things especially as the errors being thrown were around P310B - Low Fuel Pressure Regulation - Fuel Pressure outside of specification initially and then after repeatedly forcing the issue to log data I got P0087 - Fuel rail/system Pressure Too Low. I did some reading up on this and monitored the rail pressure and the efficiency of the Lift pump in the tank. This was showing outside of the tolerance levels (at idea was showing around 65%) and when the issue occurred the rail pressure dropped dramatically. New lift pump was bought and fitted, after which the issue was still there but was getting worse (car would not go above 1500rpm). New High Pressure Fuel Pump bought along with Cam Follower cap, Fitted the new HPFP and things seemed better but the issue returned after a prolonged drive. New G410 low-pressure Fuel pump sensor, fuel filter and spark plugs all fitted and although it's improved things I cannot deploy any sort of load and have to nurse the throttle to get it up to speed. The car sounds great, no weird noises on idle or when the car is being driven. I'm now at a loss as to what the issue could be but wondered if anyone had any suggestions. Just to recap the list of new, genuine Audi parts fitted are as follows Complete Lift pump in the tank HPFP which included a new Fuel Pressure regulator G410 low pressure sensor Cam Follower cap (old one was hardly marked) Fuel Filter Oil Filter and Oil Change Spark Plugs (NGK Iridium BKR7EIX one stage cooler) I'm not opposed to spend more on the car to fix this but don't want to take it to Audi unless I really have to, seeing as I've shelled out over £650 already. I'll gladly stump up a few beers and a chat for the person that gives me the winning solution to my issue.