Nissan Repair: CARS, cold air intake, premium fuel

Question
Sir,
I've a car that gives me a mileage of 20km/ltr. Could you suggest me some means by which i could increase my car's efficiency.

Answer
Mun,

A cold air intake and low restriction filter like a K&N would aid in mileage increase.  A low restriction exhaust will help on the back end.  Advancing your timing by one or two degrees will help, providing you are using premium fuel and the engine does not knock.  Increase the air in the tires to the maximum on the sidewall.  Make sure the brakes are in good order and are not dragging.  Remove all non-essential items from the vehicle to reduce weight.  On the highway keep the windows up and closed to reduce drag.  Using synthetic oil of the lowest weight allowed for your car will reduce friction on the engine and load on the oil pump.