My 89 Jetta diesel speedo shows a 5 mpg error on the slow side at 25 mph (shows 25 and clocks at 30) and almost 10 mph at 55, showing 55 and actually doing 63. To prevent getting pulled over for speeding, I attached tiny paper numbers around the speedo dial, showing actual speed at critical points, like 25, 35, 55, 70. Doyt