I beg to differ. Replacing the speedometer WAS the fix for me. Now, I am not saying that the problem is purely the speedometer in all cases, but in my case, with these symptoms, it was the problem, and the solution was replacement of the speedo. It is quite possible that a sending unit in other cases may actually be the problem.
I'm not sure what it is but my bird is a good candidate for research because my speedo only works occasionally rather than screwing up occasionally. Unfortunatly I can't get my dealer to do or try anything at this point. I think I'm going to try the number that engage provided.