96 Sebring Convertible Tach and Speedo going up and down like crazy

96 Sebring Convertible V6: Have had this problem for a while now and the problem is getting worst. When I start the car in morning the tach and or speedo will start going up and down on their own. Cannot put it gear, etc. Shut down car and restart it and everything is fine and off I go. Now if I let the car idle for awhile the motor will race up and down and looking at the guages I see the tach and speedo also increase in rpm and mph when in park. Strange indeed. The other thing is my battery goes dead now if not started everday since the speedo and tach problem started. Can anyone help me out please.