Others will chime in but-
How is your engine coolant temperature (ECT)?
Any problems with engine coolant like thermostat being changed/
Your instrument cluster temperature should be very slightly to the left of center when fully warmed up.
This is just a question, no need to replace anything at this point

 

Temp is good. My mechanic suggested might be computer but it is also new. This is my fourth mechanic since I bought this truck and had the new motor put into it. Since new motor, about everything has been replaced, some things twice like plugs and O2 sensors