Coolant sensor issue?

[Blind Dog]

The temp gauge on my dash doesn't seem to be working properly. The needle only rises just above the cold mark, and then drops below it again after driving a couple of clicks. I'm presuming the drop is because the thermostat is opening up properly when the engine is warm, and that there must be an issue with a sensor preventing the needle from attaining and staying in its normal 'half-way' position. Thoughts?

 

[just1me]

Just recently I had changed out my thermostat housing, thermostat, and sensors with all new pieces, and my temp gauge also started acting funny. I went through all the other check list trying to figure out what it was, but it turned out to be a faulty new sensor, replaced it, and all was back to normal again.