Whats up with my speedo?

The cable turns a pretty close 90 degree turn just about under the drivers seat. There is where the bounce comes from. You can disconnect just the instrument end, pull the cable out, clean it w/ brakeclean and push it back in with white litium grease and hope that cures it or.. go a step further and disconnect the trans end of the sheathe also and flush the empty sheathe with brakclean and compressed air ( from the top down ofcourse ) before reinserting the cable w/ grease.
I've seen the cable wear through the wall of the sheathe before it finally breaks.