my friend has an 84 gsl and his speedometer works but it sits way below zero so when the needle says 0 he is going like 45. his tach gets to like 3 and sticks and stays there and some times it just freaks out. Any ideas would be greatly appreciated thanks.

 

Spedometer is most likely a bad cable. Tach might be a the result of a trailing ignition issue (coil, ignitor).