[Whitey]

I just started driving a Honda Civic recently, and I noticed right off that the speedo was reading fast. I timed several miles on the Mass Pike and determined that the speedo displayed 105% of actual speed [edit: corrected %]--but the odometer seemed to be accurate. I was able to confirm my speed using the radar near a local school.

I purchased a ScanGaugeII [edit: fixed typo] soon afterwards. Interestingly, SGII displays the correct speed. SGII also displays slightly lower RPM than does the Civic's tach.

Of course (as already mentioned), the odometer needs to be accurate for true MPG figures.