my sppedo seems to get stuck around 20-30 mph and if i go faster, I have to hit the dashboard a couple time to knock it loose so i can see how fast i'm going. this is the same for when i come to a stop. it gets stuck on the way down and i have to hit it to get to 0mph. what could be the problem? I put in the macewen overlays but that was a while ago and this problem just started.

 

If it is a cable driven speedo, it could be that it just needs some fresh lubrication. My symptoms weren't quite the same (my speedo needle wouldn't sit still), but I imagine that it could cause it to just plain stick.