Thanks for the thoughts. I am located in Naples, Fl where the temp hovers in the 70-80 + range most of the winter. I have had the treads, sidewalls and valve stems checked to no avail, and we live in a very secure gated community, so the kids don't get at the car. I think you may be correct though; it just may be a slow loss over an extended period of time. The other possibility that just came to mind is that the dealer rotated the tires within the last two weeks, and perhaps they did something inadvertently. Guess I will just have to watch it closely for a while.
By the way, I have been carrying about 34 psi. Is that too much?