hi everyone
im writing because i have a problem with my love.. and the story is

8/28/13bought with 18,000 + km

After about a month ι get it to a general service (oil filter blends check spark plug etc) and a full check to know if is there something needs something

before service the fuel light turned on at about 170-180 km
after the service the light turned on at about 130 km
the mechanic aftem my complaining about increased consuption trimed the fuel mixure a lot of times but nothing better .. the fuel consuption was about 7.5 litres per 100km
after going to a lot of mechanics that noone could find and fix the problem the consuption suddenly was normal again (fuel light at 170-180 km ) that means 5-6 l/100km
after 20k klms the problem come again ..
i checked the valves ...ok
cleaned the air filter ....
cleaned the fuel injector ..
but the problem remain ..
i dont know what to do after all these ...
mixture is at no 5
tps position at 17
and all the other settings are ok ...
what to do ???????