New car buyers biggest mistake. You don't know your credit score?

Most people know their blood pressure and cholesterol level, but few know their own credit score. This is your most vital stat, and directly controls how high an interest rate you'll pay on your car loan. Show up at a dealer without knowing your credit report, and you might as well give them your checkbook. A car dealer should never know more about your credit than you do. Besides, you might find an error in your report preventing you from getting a loan.