I agree with Brandon, I think its the manifold gasket or a vacuum hose is leaking. This is very common for the six cylinder. You would want to spray the carb cleaner though around the outside of where the intake manifold meets the cylinder head. If it is a leaking gasket then the idle should smooth out momentarily. Usually the leak is at the No 1 cylinder. When mine leaked there were no codes but the car had a little more get up and go due to the leaner fuel mixture.

With a bad temp sensor you would find that your mileage would be lower and the car lacking some power.

Hope this helps.

DanR 94 964 211k miles