I've had a really annoying problem with the speedometer ever since getting the Shelby Lancer running again last summer. At first, the speedo would skip around all over the place (rather violently) whenever the car was moving forward. That has since smoothed out, but now it is always showing about 25 MPH above the actual road speed. At a stop, it reads about 25 MPH as well.

Is there a chance the clocking of the needle itself could have gotten off when it was doing the skipping around? If so, is it possible to pull the needle off and reattach it at zero to fix it? Also what is the best kind of lubricant to use on the speedometer cable? I was thinking of removing the speedo cables, and flushing them out with brakleen and trying to lubricate them with graphite or something.