Tire pressure is one of the most important factors in maintaining your car's handling and fuel efficiency. Overinflated or underinflated tires can lead to a number of problems, so it's important to know what the correct PSI for your car's tires should be. In general, passenger car tires should be inflated to between 30 and 35 PSI with 32 being average. You can find the exact number for your car inside of the driver's side door jam.