How do I check and fix low tire pressure myself?

To check tire pressure, you need a tire pressure gauge, which costs a few dollars at any auto parts store. Remove the valve cap from your tire, press the gauge firmly onto the valve stem, and read the PSI displayed. Compare it to the recommended pressure listed on the sticker inside your driver's door jamb or in your owner's manual, not the number on the tire sidewall. To add air, use a gas station air pump or a portable compressor. Press the air hose onto the valve stem and add air in short bursts, checking frequently with your gauge. If you overfill, use the small pin on the back of most gauges to release air. Replace the valve cap when done.