Faulty temp gauge or thermostat?

[MahFiVeOh]

Lately my temp gauge seems to work only some of the time.I have a 25-30 min drive to work and sometimes it doesnt move at all.I replaced the thermostat last year and was wondering if thats the problem or maybe my temp gauge is starting to crap out? Any tips?

 

[Beasty306GT]

could be a bad temperature sending unit...front right of the intake..mine did the same i replaced it and the gauge worked

 

[HISSIN50]

You'll need to get a real gauge to check the stock gauge's calibration (the stocker isnt accurate enough for diagnostics anyhow).