Chevrolet / Spark
Low Mileage

I checked the mileage on my Chevy Spark LT 2008 Petrol last month.

I am getting only 8 km / litre in the city and 13 km / litre on the highway

Chevrolet's mileage for the spark is around 18 - 19 km / litre

The service center advised me to drive more on 4th and 5th gear in the city!!!

Will this compensate for 10 km difference in mileage???

Can anyone help me with problem?