Speedometer Off

[electro_cal]

I just bought a 94 gt. my speedometer is about 15mph slow. the tires are 245/45/17 which is correct. the car is pretty slow, so I dont think the gears have been changed. what would cause this? and how do I fix it?

 

[addermk2]

Check your gears before doing anything. You can't proceed until you do.