gauge problem
 

I own a 93 auto passat VR6, and my gauges have stopped functioning properly. My tack and speedometer will go from not reading anything at all to reading around idle on the tack and a little bellow 20 mph on the speedometer. They do this if the car is sitting in idle or if I am driving. There is no connection between revving the engine or hitting bumps with the gauges starting to work or not working at all. My gas gauge and oil temp gauges are working fine it is just my tack and speedometer that are not working. The digital displays in the dash will randomly display numbers that are not connected to the current state of the engine. Any tips or help?