My 95 does the same thing. I had to replace the vss several times. I did find that metal shavings in the rear differential lube can cause the vss to give false readings at speed. They are magnetic and will pick up metal to distort readings.
My abs light is also on all the time, can't find out why with all test done. I just live with it.
The cruise control would some times work, some times not, and have a mind of it's own. Replacing the pressure switch on the brake master cylinder sloved the problem.
Ford's of his age are known for having speedometer problems. Sorry I can't be of more help. Good luck.