So I'm having problems with the speedometer and odometer on my tercel. The speedo needle bobs up and down whilst driving. Generally, the odometer works fine however it gets stuck when 4 digits (thousands) have to rotate ie. it does not work properly when turning from say 70,999 to 71,000. Cable is fine....any idea what the problem could be? Secondly, is the speedo from a diesel tercel interchangeable with that of a petrol tercel?