So, I had an odd issue coming home tonight with my car. On my way home (which was about a 20 minute drive) my car started idling unusually high...like 1300rpms. It didnt start doing this till about 3 blocks from my house, so i just drove home, put it in park, and popped the hood.

Everything looked fine, no vacuum leaks or anything, so i went back in the car, and noticed the coolant display said the coolant was 79*? The coolant was at 180* within the first 5 minutes of me driving....so idk whats up with that, but im guessing the ECU saw the 79* and put me in open loop and raised idle RPM to help warm up the car. Anyone have any ideas why this might have happened? I'll check tomorrow morning and see if its still gonna be stuck at 79*, or if it was a fluke thing. I searched for this problem, and the only response that came up was this:
https://www.cobaltss.net/forums/show...t=coolant+temp

which worries me, since i dont have a warranty anymore, and he never got an answer to his issue

anyway, any help would be appreciated

 

The coolant temp sensor could be bad or the connection,check the connector and spray some contact cleaner on it to make sure there is no oxide.
The readings are resistance based so if the connection is bad the the readings will be flaky.