The data indicates that all sample vehicles of the Audi A6 (2011-15) 4-door saloon with the specified trim and engine type are equipped with a 2.967-litre (approximately 3.0L) V6 engine, and all use diesel as their primary fuel. This consistency suggests that during this model period, the 3.0 TDI V6 engine with diesel fuel was standard across the specified variant, highlighting the vehicle's emphasis on diesel technology and engine capacity uniformity within this range.