what should my psi be on my tires.

On the driver's side doorjamb you'll see a sticker with the tire inflation pressure specification. Sometimes it's on the front passenger's side doorjamb too. If you're driving somewhere to add air to the tires, increase the pressure 4 PSI when you fill the tires. You'll need to do that because the pressure on the sticker is for cold tires, after driving even a short distance, your tires will be warm so the pressure should be 4 PSI higher. Hope that helps! Jim