I'm pretty sure the temp sensor is right on the back side of the air filter box. Your sig says that you have a cone filter, so I'm not sure where it would have been relocated on your car.
Generally, if the sensor fails it can go to ways.
1) It shorts out reducing resistance. This would make the car think it's hotter and and trim the fuel a little.
2) It burns out causing increased resistance which makes the car this it's colder and adds a little more fuel.
Since your issue presents on very cold only, I thought maybe it was acting like it's hotter than it is.
