Is it normal for a 2012 Sunny automatic to show a fuel consumption of 7.8 after running 1,000 km on the highway? The usual city driving fuel consumption is 8.9, is it considered high? How can I check and reduce it...

Check if the throttle body, fuel injectors, spark plugs, EGR valve, and air filter are due for replacement. Continuously add 0.05% PEA in the gasoline to inhibit carbon buildup on the back of the intake valves and piston surface. Remove the first section of the intake duct and install a vortex gasket behind the throttle body.

If your speed is around 140, this fuel consumption is normal.