1986 Mustang 2.3L Gauge problem.

I have a 1986 Mustang 2.3L. I have noticed that my temperature, fuel and oil pressure gauge read incorrectly throughout normal operation of the car. Once in a while the gauges will jump back up to where they should be but then shortly return to read incorrectly. Does anyone know of this problem and how to cure it. If so any suggestions will be greatly appreciated.
Thanks.
~barry~