muddphish

I have a 94 S-10, 2.2, 5-speed, the speedometer is off 5 miles per hour at 35, then 10 at 45 etc...

GSsg98

I own a 93 / 4.3L / Manual 5-sp....and mine does the same.
I bought it a couple of years ago and just delt w/ it, but would like to fix it too. My S-10 had the rear end (differential) replaced just before I bought it (from 3.08 to 3.42 ratio).

Somebody out there correct me if I'm wrong, but I think we need to put a Scan Tool on our PCM's to read the right Gear Ratio.

NoSpudsInIdaho

So what size tires are you running on? And what size is on your door sticker? Running different sized tires from stock will throw your speedo off by a percentage. What you're describing is about 12%, or about the difference from 195's to 215's. Changing the ratio in the differential will throw it off too.

Years ago, when I bought my first S10, I put bigger tires on it for off-roading and put my speedo off nearly 20%. At that time, someone made a converter that went inside your dash between the speedo and the cable. It would gear up or down (I went down for larger tires) by a set percentage to bring you're speedo within 1 or 2%. Maybe someone out there knows where to get one of these things?