Jerky Speedometer at 40-50+

[sparkin88]

So the other day I pulled my gauge cluster... just to look at it and see how difficult it actually is to get to the circuit board for the LED color swap. I didn't pull the needles off but, noticed they were loose as in would go to whatever MPH, the tach is fine and is smooth during operation but after assembly and putting the speedo back to 0mph. I was driving on the interstate and noticed there was not way I was going the speed it said I was considering I was keeping up with traffic.. Noticed the needle was lagging and was very jumpy instead of smooth.

Let the car sit a while and seemed fine, got on the interstate, okay seemed like it corrected itself. then on a backroad I gave it a little and 40-50 range it started jumping again then at the stop sat below the 0mph mark. Any ideas?