What would make my temp guage act like this?

It works normal when it is cold and warming up, but every time I get it on the freeway it maxes out on cold. Then if I park it and leave it running a long time it will start to work and show the temp, until I get on the freeway.

There is no way the engine is getting cooled that much on the freeway.

I do however, have no license plate blocking the air dams.
I did that a while ago, and it really helped, but it never totally dropped the temp gauge.