Hey, I have a 2001 Jetta 1.8t with 137k miles. It has been working great until here recently. Replaced water pump, and timing belt at 116k. Now it runs too cool, yeah its crazy. At idle after running for a while, temp will get up to about 100 deg. then drive it and it goes down. Replaced Engine Coolant temp sensor. Still does the same. Replace FI temp sensor. Worked for half a day. Temp went right back to norm. 190 and drove around went to the store and light came back on. The temp went down on it again. The code is "problem with cooling system". It's not overheating. I drive it 110 miles per day to work and back doing about 75 mph to 95 mph. I do reg maintenance all the time. I'm lost on this one. It's not the water pump or it would be overheating, and that is easy to see. Faulty wire some where???