My fuel gauge sometimes sticks, which can be a problem if I am on a long journey and don't notice that it has'nt moved. Solution is to turn off the ignition and start the car again. The gauge wakes up and normality resumes.
I had a similar problem with the oil pressure gauge, but I have only noticed it once.
I don't know what causes this, but I don't think it has anything to do with the earth. More likely to do with the quality of the individual gauges and condensation build up inside the gauge.
