OK, but the accuracy of the "instantaneous fuel consumption" is my second concern. My first concern is the time needed by the "instantaneous fuel consumption" to hit the 0.0 l/100Km (or 999.9 mpg). Why it needs about 10 seconds for this? The engine is under zero load since the moment I lift the foot from the accelerator pedal. It looks to me that the "instantaneous fuel consumption" behave like an "average fuel consumption for the last 10 seconds". Can you please check if your C3s are behaving the same? If not, I may have a problem with the engine management. During drive tests, I've checked the "instantaneous fuel consumption" on a Skoda Fabia and a Seat Cordoba and for these cars the "instantaneous fuel consumption" reaches 0.0 l/100 KM very quickly (about 2 seconds from the moment I lift the foot from the accelerator).