Quick question : the fuel consumption is huge (twice than it should be), and after i push the pedal a little , it takes alot of time to go back to the idle rpm of about 800-1000 (sorry my english is not that good at technical terms). What can it be ? I've just cleaned the fuel injectors , and the air filter has been changed 1000Km ago .
try spraying the inside of the air flow censor with a lub like WD40 if its the swinging arc type as it sticks from time to time
if its the hot wire type then check the various sensors around the engine to see if they have a good contact as this gives problems at times
after that its down to checking the silly bits like throttle bodys sticking , fuel pressure to high (rergulator sticking) and a whole load of heart ache of bits and bobs