My car, Jaguar 2.7 diesel S Type has on board instant MPG read out. When I use the Torque read out it is miles different from the car one, sometimes by as much as 100%, i.e. Torque says 25mpg, car says 50mpg.

Which is right do you think?

You’ve probably sorted it after 6 years, but as a new member I’m interested in all the solutions to various problems.Your car readout is of course the more accurate. The trick is to use the MPG “Trim” function which is found when scrolling down through “vehicle profile” in the menu button bottom left. I also was getting a Torque readout about twice as much fuel consumption and I’ve reduced the trim from 1.0 down to 0.7. At 0.75 it was getting closer, so I’m confident I can fine tune it over the next few journeys.