I have a 92' RS 5.0 TBI. My speedo reads 35-40mph at 25mph, 50 at 35, 80 at 55, etc. It hits 110 (and governs) when I'm only doing 75. The VSS has been replaced with no change, and the computer reads the same as the speedo. What do I do next?

 

Is everything stock? Did it work at some point? If its stock then its the sender, buffer box or the spdo itself I think. If the rearend, tire size, transmission ect. changed thats a different story. You will need the correct spdo gears or a box to change the signal.

 

soumds like my IROC, I went from 2,72 rear gears to 3.73, and the speedo reads about like yours

 

I think everything is stock. I have only had the car a couple of years though, and it hasn't worked. Is there anyway to test the buffer?

 

Just pick one up from a junk yard or from Hawks. Should only be a few bucks.