It has a very high mileage, its about 275.000 km, i intend to get new engine parts as soon as i get the money for it, and i currently use 10w40 oil, i am thinking of changing to 20w50. I am concerned too about it's spending on gas. It is making about 5 km per liter. Already changed fuel injector, trying to fix this, but it is still spending a lot of fuel... Any tips? I am sort of a noob at car mechanics...