Pathum Fonseka

i brought a daihatsu hijet cargo 650cc EFI van,milage 69000km when buying, two months before i have this problem 1)many people taold van will run 15km per litre of patrol..but sice i start using it runs only 10km without A/C,and around 8km with A/C..i m little bit confuse about the efficency of engine.. 2)and having strong petrol smell when i strat the engine..(may be unburn feul) plz give some advice how to improve this