Gauge Problems

I own 2 LeSabres presently, a 91 and 90 Limited respectively, and also had an 89 Limited.
All three cars had analog gauges for oil pressure, water temperature, volts etc. It seems that all cars have had problems with the gauges. On the 90 the water temperature would operate properly for a few minutes and then would spike to the highest temperature. I switched clusters from the wreckers and it eliminated it. On the 91 the temperature gauge has also begun to do this. I had the cooling system checked and it's fine. I replaced the water pump and thermostat 4 months ago. Now the oil pressure gauge on the 90 is bouncing around. The cars are running fine otherwise.

It is just the guages themselves. I recommend cleaning them with a contact cleaner.