2006 Pontiac Grand Prix Odometer

Try tapping on the gauge cluster to see if it moves. If it does it may need a new cluster.

Where is this found on the 06 Pontiac Gran Prix?

It is where you look at the gauges tap on the dash above it and on the plastic cover where speedometer is. To see if needle moves back.

50 mph = approximately 90 kph so check your speedometer and make sure it's reading MPH. On mine you can change the reading from Kilometers to MPH through the DIC. There should be a red light showing mph on the left side of the speedometer gauge, kilometers per hour will show on the right. A mechanic fiddling with the computer could have switched the reading.