I just got my speedometer up and running (new drive on the hub and greased the drive behind the guage). It works great. But for some reason, yesterday, at around 80mph, it bugged out a little bit. The needle started to bounce and quiver, varying about 1000 rpms. I stared at it for about 5 seconds, and then it stopped. Since this happed, I've gone this same speed and faster, but can't reproduce the problem. The guage insists on working beautifully now. Any thoughts on this?