So I've been sorting out the new to me 2002 ep3 that I picked up this month... One thing I'm not getting figured out is my speedo accuracy.

I'm on a fresh set of stock sized tires (195/60r15), but the speedo reads really high.

I've verified against GPS and radar speed displays and let's call it 15%, But that varies with speed, down low (40kmh) it's about 20% high.

I checked the trans code and a previous owner replaced the sir trans with a base RSX so the final drive is 4.389 instead of 4.764. if using the sir VSS, that would be 8.5% high, but the thing is I took 10 minutes at looking at the VSS and it did not want to come out. I bet it's from the RSX trans and hasn't been out. So it should be correct to the FD.

Could it be the speedo stepper motor itself?