Is it out against the Focus's digital reading in diagnostics mode? All the analogue readouts seem to have the needle put on ~5mph above the actual internal reading from the PCM.

If you want it more accurate pull off the needle and reposition it, though that is a bit difficult as your driving.

If the digital reading is out then there are 2 choices.

1) Get a Ford dealer to recalibrate the PCM, although I believe this is done in terms of wheel and tyre size. Or,

2) For less money, buy a SpeedoHealer and install it in the VSS line to the PCM. That can recalibrate the signal to whatever you want, well almost. Its what I've used to recalibrate a MT285 box for use on a standard Focus.

Martin