I have a 95 gsr turbo with an aem ems and a serial gauge the gauge said that my car got up to 220 230 but the stock gauge never went to the half way point. What should i believe? It is still the stock water temp sensor.

 

The stock gauge could sway 30 degrees from normal temp and it wont move. They are very inaccurate.

I hate to tell you to trust anything aem, but the aem is right.