Quote Originally Posted by SyntheticShield View Post
The 180* T-Stat I run (its drilled also) puts my cruising temp just above the first major mark, usually about the first minor mark after that and it will go up and down around there. In town it will go up some but I have my PCM programmed to kick on the fans around 185 I believe.

You can indeed run an engine too cold. If your thermostat were ever to stick open you will find that it will run cool enough to cause some stumbling at idle and you will most certainly use a bit more fuel. 180* is about the coolest thermostat I would ever use in a passenger vehicle.
I'll keep an eye on it then over the next few weeks. From the code I was given, I also read that it could be a bad temperature sensor. I don't think the new thermo is stuck open, and there's been no code thrown since I put the new one in and cleared the error. But could the bad temp sensor keep the coolant flowing? There's been no stumbling at idle, and a quick computation of the MPG average was 24, a mix of highway and city. About right. Then again, maybe the gauge is just wrong. I believe my ODBC2 code reader might also monitor temperature. Worst case, I get the Aeroforce gauges to go in the Impala pillar gauge holder and check it out in the GP for a while.