Boasts 33 Highway MPG and 24 City MPG! KBB.com 10 Best Sedans Under $30,000, KBB.com 10 Most Comfortable Cars Under $30,000. This Kia Optima has a durable Regular Unleaded I-4 2.4 L engine powering this Automatic transmission.*You Can't Beat the Price with These Options... via HomeNet, Inc.