Both sensors are new. Going to try to get a scanner on it tomorrow.
Thanks
This is an older thread but I just started to have the same issue. I am "mostly confident" that the Yukon was running much hotter on average than the 160ish that it tops out at.
1. The heater cranks out lots of heat.
2. Even when it is 110 deg and I am idling around the temperature gauge never gets above this mark. I believe it used to be much more centered.
3. I flushed and filled the radiator 8 months ago. Replaced items with the following parts: Duralast Radiator Cap 7616; Fail-Safe Thermostat 7228-195
4. There was an initial spike like you had but it was because I had air in the system still. I pulled over, released the vacuum, topped it off and cleared any remaining air. I have run the truck for 8 months without an issue so I don't think this affected any of the sensors or engine.
5. Now to the sensors:
There is a good video on how to test the driver side sensor and wires
here. But since you swapped out those parts that is not an issue.
It is possible that a bad ground somewhere could be affecting the electricals. I am about to upgrade some of my wires next weekend and I will let you know if that magically fixes the issue. I will post the upgrades in my
Project 99 Yukon thread.
Did you figure out the issue? Any help on this issue would be great.