Shares of the used car dealer fell after a disappointing earnings report and a delay in hitting a sales target.Shares of CarMax (KMX -9.12%) were pulling back today after the country's largest retailer of used cars, both online and in-store, posted disappointing results in its fourth-quarter earnings report.As of 3:30 p.m. ET, the stock was down 9.5%. CarMax hits a bumpy roadIt's been a tough market for used car dealers as high interest rates have significantly raised monthly payments for buyers, and prices ...