Question: are kia optimas good on gas?
Answer: Kia Optima MPG & CO2 The Kia Optima's 1.7-litre diesel engine returns 67.3mpg and emits 110g/km of CO2; choosing the automatic gearbox sees fuel economy drop slightly to 64.2mpg. ... This comes with a 2.0-litre petrol engine and an electric motor, which together return 176.6mpg and emit just 37g/km of CO2.