My Maxima (96K) recently started reading cold when at hwy speeds. The needle rests just on, or above, the C on the temperature guage. When in slower traffic, or idling, it shows normal (ie. midway between hot and cold) readings. I am going to check the Coolant Temperature Sensor tomorrow. Has anyone had this problem or heard of it before? I have a full radiator and no leaks that I can see or smell. Should I be driving at all until I get this fixed?