i have a 88 vert. i took out the gauge cluster to change a couple bulbs out and when i put it all back together the speed-o bounces around.. ill be doing 30 and it will be bouncing from 50 to 180. even when im just starting to go it starts to bounce around what could cause this?

 

Bad ground/connection could be the culprit. Make sure the connector is pushed all the way into the back of the cluster.