The average car speedometer may be off by a few mph There are several GPS and 3rd party apps that show your actual speed The speedometer, of course, tells you how fast or slow your car is moving when ...

Fixing the speedometer on my Honda S2000, which as you can see clearly reads too high. While traveling at a GPS verified speed of about 80 to 81 miles per hour, you can see the car’s speedometer is ...