the temp gauge on the jetta never worked when we got it. Well a month later on the interstate it went to 190. 3 days ago it starting to work. Its never above or below 190. is that were its supposed to be.:confused:

Correct. You do have a failed coolant temp sensor. It's the sensor on the driver side of the cylinder head. The new one should be green and not black. It's about 30 dollars.