I had some misfiring and CEL on cold starts in the morning, I been following a few threads about build up in the new Audi. Bought it into the Audi dealer today, and they put a scope in there and confrim the build up. Audi is asking them to put in some B.S. injector cleaner and drive it for 60 miles. The SA said this procedure doesnt work but they have to do it to make Audi happy. After that, they will clean the valve area, behind the valves and I think the upper conbusion chamber with some solvent. The dealer said they have done 3 of these this month and all on brand new Audi. Audi is suppose to have a new ECU program that will retard the timing to provent this problem. According to my SA, this only happens in a small percentage of new Audi. I will update you guys in 2 or 3 days when the car should be ready. Meanwhile, I have a 2009 A4 loaner, not a bad car at all, very zippy and handles nice. I dont miss my A6 as much as I thought