My 97 PSD never seems warm up. The stock gauge wont come off cold. I went and bought a sunpro gauge. Tested it in some boiling water first and it read about 210 when it started to boil. It never reads above 130-140 in my truck. Outside temp is around 40 degrees. I also still have good heat. What t-stat should be in my truck? It is stock with the exception of a superchips tuner 3" downpipe and no resonator. What temperature should it be running at? Also is there a temp sensor that goes to the computer and a seperate one for the stock gauge? i had to take the 1 for the stock gauge out.