Originally Posted by choate
I just got the p0128 again. Didn't replace anything yet, just cleared code. It stayed off the first time for 5 months. The second time for a week. I'm gonna change the thermostat and see if that helps as the heat gets decently hot, but it takes is a long time so I'm hoping that's my problem. Any info is appreciated.
Assuming our cars use the same thermostat, get the motorcraft part, its the only one rated for 193, and test it before hand. Motorcraft part RT1193 and $36 on amazon. Also keep your old one just to have (wish I would have). I still think there is something a little different between the old ones and the new ones as far as functionality such as maybe the old one had a lighter spring on the bypass disc of the thermostat? The other brands are 180 (and they start opening before that). If your car stays under 175 too long then that is usually what sets off the p0128. You might just need some cardboard in front of the radiator for the winter too.