How does a car run cold

Yes, a bad sensor like Carl said.

Check to make sure how many coolant temperature sensors there are in your engine. With a 2001 car there will be one for the engine management computer and one for the dash gauge. I have a '98 GMC and have the same issue with the dash gauge showing a low coolant temp. I replaced both sensors just on the notion that if one is bad the other might be also. The computer temp sensor on my truck (5.0L V-8) is located in the thermostat housing. The dash gauge sensor is located on the side of the engine down near number one spark plug. You may have to to some online sluething to find you sensors.

... A faulty coolant sensor that always reads cold may cause the fuel control system to run rich, it may be sending the wrong info to the computer and the guage. make sure there is no air in the coolant system, and it is full. see if coolant resorvoir is full when hot. if all is ok, change coolant sensor. good-day!