This is a new to me car which PO told me for some time has had this condition. Both the fuel and temp gauges are wound way over past full and hot clear to the speedometer arc. It also once in a while has the speedometer ( all analog type gauges) start reading slow and bouncy. The fuel and temp do move a bit sometimes but not much. I have read the entire cluster is shot but hate to go buy a new one just to see if it works. What is the usual cause of this and can a ground problem often cause this like with older cars?