Pegged Temperature Gage - Engine Cool

1991, 2.5 liter Engine is not overheating and runs fine.

Gage started going erratic at low rpm's. Would settle out with higher rpm. Eventually pegged high and stayed there. Replace temperature sensor and it worked for a couple days. It went through the erractic stage and eventually pegged high. Every now and then at high rpm's the gage will come into range for a second. Replaced the temp sensor again but no good. Replaced the throttle position sensor but no good.

Any ideas?

A pegged gauge as this usually stems from a sending unit problem:

If pegged = shorted to ground

not reading at all = open in wiring.