The car hasn't been driven in 24 hours, sitting in the garage all night. Do I check tire pressure now? If it is low and I drive in the 95-100 degree heat for 10 minutes to the station to add air, how much do I add? Won't the drive in the heat have inflated the tires somewhat? How often should tire pressure be checked? Seems like everytime I do, air leaks out of the tire. The toyota dealership is much too far away to take the car in for just this, but I think my mileage has dropped since I bought the car in late May, and I wonder if it could be tire pressure. Thanks for any advice.