Hello,
the speedo of my 3.7 Roadster shows close to 20% too high speeds compared to my GPS. Even my smartphone-GPS confirmes that it shows too much. After some internet research I think that the car software was fed with wrong informations about gearing, rear axle ratio or tire size at the factory. Can a normal dealer correct that with his equipment or do I have to visit a tuner which offers speedo correction? Have you ever heard of such an issue?
