guys my friend's 1.0 L vitz was acting weird. earlier it was giving 600 km in each tank, now it had dropped to less than 400 km. it was idling rough and making strange noise. yesterday went to magic motors model town.
injectors were cleaned ultrasonically
ecu was scanned and he diagnosed that oxygen sensors were acting lazy hence ecu could not adjust air/fuel ratio efficiently.
throttle body was cleaned
and even looked inside the engine using a camera that goes in through spark plug hole.
car is smooth now, i think cleaning the sensors played the major role.
we paid 2000 for all this. and these people work by the book, i saw workshop manuals with them and they were educated people. not tukka mechanics.
i highly recommend paying them a visit if you have bad fuel economy.