Audi's Cylinder on Demand (CoD) system is a technology that shuts down two or four cylinders in an engine to improve fuel economy. The CoD system can switch between two- and four-cylinder modes in as little as 13 milliseconds. Some say the CoD system works so well that it's difficult to notice when the engine shuts down cylinders. Red, 2 owners, UK Cars 4 Less Driving You a Better Deal - Please Call to View, £12,000