I updated my I3 to repetier from the anet firmware that came with it and everything was working fine until I ended up shorting out my thermistor.
I replaced my thermistor and the reading was about 10 degrees lower than ambient so I just rolled with it for a while and experimented with temps until I found 150° was about right.

Now after another firmware change it reads ambient at -15... I did the same thing I did before and took an infrared temp gun and just rolled with it, well now I'm about to start experimenting with different kinds of filament and would love for my temperature reading to be accurate so I'm not going in blind.

Does anyone know what in the hell could be going on? Or have anything for me to look at, or something I should upload like firmware?