I have a 2006 Mercedes C220 CDi Sport Auto. The car has 111500 miles and I purchased it two weeks ago from a garage. Today after driving to my mums, the car was warmed up and I put my foot down on a dual carriageway, first time Iv really had chance to do this. The car picked up well and it was only when I approached some traffic lights I noticed a fault. As I pulled away from the lights from a standing start, it felt like the car was stuck in 3rd gear and it wouldnt change up or down. I also tried to press the Sport button but it remained in comfort and wouldnt switch between the two modes. I got to my mums, switched it all off and then restarted it 5 mins later. I took the car for a drive and all was well once more. Now I have a warranty with the car and will be speaking to them on Monday. Is this a common fault and has anyone any idea of what it maybe and would it be costly to fix? Also, Iv noticed that when pulling away from a standing start, it feels like you are always starting off in 2nd gear but I was thinking this was normal as its in comfort mode? Really concerned as I have only had the car two weeks and so far I have loved it. Taking the family away on holiday next weekend and I am worried that all is not well. Any advice?