I went throught this issue somewhat myself. My guage would peg itself once in awhile. I believe you should change the thermostats. If that is not your problem then it most likely is the temp sending unit on the motor. The digital dash would respond to sender changes quicker than a analog guage and could be a little more sensitive. If you know for a fact that you are not overheating then the temp sensor would be the first thing I would change. I just ignore mine but will probably change it later this fall, just in case…