We had a really cold night the other night and now my TPMS has popped up. All of my tires are in the 28-30 psi range but 1 in 1 psi lower than the others and that is what is triggering the warning. I'm going to pump them all up later today when I get gas and was wondering what others are setting their psi at for cold weather and best mpg. I have a Touring with the 18" tires.