Assalam Waliqum,
I have Corolla XLI 2015 Manual Transmission. my car gives me very bad fuel average almost 10 to 11 Km/L.
Replaced Spark Plug, Fuel Filter, Fuel Pump and clean the Catalytic Converter, Oxygen Sensor and MAP Sensor.
In short i did general tuning (Throttle body and manifold were Cleaned ) of the car but still it did not gives me a good fuel average. As this car was on CNG, and CNG has been removed. no blockage of air. Still mechanic not finding the root cause of this problem.