This happened back in August of 2011, reposting it here to build up the archives.
Coming home from Carlisle, the gauge was 2 ticks left of center.
No check engine light. A look into the DTC list revealed the P0128.
I watched the engine temp as it got to 180 degrees or so and stayed there.
After verifying that the coolant level was ok, I swapped out the thermostat.
Temp gauge back to "normal".
I kinda goofed here, I didn't take a pic with a shorter run time. It got up to 205-ish in a few minutes.
And there you have it. During the three or four days it took me to get the time to fix my own TB, I documented a 6mpg loss. Moral of the story - if you have a P0128, fix it!
Coming home from Carlisle, the gauge was 2 ticks left of center.
![fc0aa4ef.jpg](http://i150.photobucket.com/albums/s98/MAY03LT/p0128/fc0aa4ef.jpg)
No check engine light. A look into the DTC list revealed the P0128.
![f4b8af4c.jpg](http://i150.photobucket.com/albums/s98/MAY03LT/p0128/f4b8af4c.jpg)
I watched the engine temp as it got to 180 degrees or so and stayed there.
![06ec6baf.jpg](http://i150.photobucket.com/albums/s98/MAY03LT/p0128/06ec6baf.jpg)
After verifying that the coolant level was ok, I swapped out the thermostat.
![5085c27f.jpg](http://i150.photobucket.com/albums/s98/MAY03LT/p0128/5085c27f.jpg)
Temp gauge back to "normal".
![a6b237af.jpg](http://i150.photobucket.com/albums/s98/MAY03LT/p0128/a6b237af.jpg)
I kinda goofed here, I didn't take a pic with a shorter run time. It got up to 205-ish in a few minutes.
![39fcc1b0.jpg](http://i150.photobucket.com/albums/s98/MAY03LT/p0128/39fcc1b0.jpg)
And there you have it. During the three or four days it took me to get the time to fix my own TB, I documented a 6mpg loss. Moral of the story - if you have a P0128, fix it!