I've already tried bleeding it, no dice. Grounds are all fine, I've literally tried everything I can think of and then some...
If I unscrew the sensor and put it in a cup of hot water, it reads fine (which is why I thought it was a air bubble or sensor position problem).
That is why I switched out the T fitting putting the sensor directly into the flow of the fluid (which I know for a fact is getting warm/hot).
I'm back to thinking it something electrical like when the vehicle is running, the voltage to the gauge is messed up or something.
IDK, again, I've tried everything