Driver Information Center Temp Guage

I have a 2004 Chevrolet Impala SS that is constantly having issues with the temperature guage in the overhead instrument cluster. I have had this into the dealer about 6 times and everything they replace seems to fix it for a day or two but that's it. The problem is it is constantly displaying a temperature that is way too low. In the middle of summer it read -11 degrees Farenheit! After the car sits over night it will read OK for a few minutes and then go whacko again. Has anyone experienced this? Everything else works in the overhead cluster but they have replaced it a couple of times along with the sensor. I think they only offered the supercharged engine on the 2004 SS, is there something with that particular engine and how its mounted that could be causing the sensor to go whacko or possibly some electromagnetic interference that is causing the sensor to fail or go bad? The dealership (Al Serra in Grand Blanc, MI) and I'm trying to help them figure it out.

It doesn't sound like a big deal but it is annoying and I use it to determine if the roads are icy or not so I can adjust my speed.

Thanks in advance for any help.