Running hot? No, I'd say not likely at all. I've had no overheating issues with the truck under my ownership.

As for a vacuum leak... maybe. I know my old brake booster was a big vacuum leak that has since been fixed. I may have some smaller vacuum leaks due to various hoses being brittle and old.

And the temp sensor? If I remember right, that was replaced a while back, so I shouldn't be having any problems with it. Though I wouldn't doubt that it went bad, as I've gotten new parts that went out prematurely. However, I don't know for sure.