when i first start the car and let the car warm up the engine temp gauge goes up slowly like normal... but when i start driving the temp gauge goes down back to C... as i keep going the temp gauge goes back up to normal usualy alil bit below half way.... the temp gauge seems to keep dropping and rising back up.. also i noticed when i go down hill the temp guage goes down to C.. so yeah idk if it could be my thermostat or just a wiring problemm .. ne one had dis happen to them or know wat the problem is.. plz help..