what shall i do???
literally the whole tanks gives me around 200 miles

iv done the whole tune up as well
which includes:
NGK plugs and wires
Injen Short Ram
Greddy EVO2 Catback
Fuel filter has been changes
Valve timing was adjusted

dont know if this matters or not but the guy who sold me, told me that the ECU was stolen some time back from this car so he had it replaced by some other ECU from a legend, but according to my knowledge legend ECU's are for a V6 engine so i didnt buy what he was saying. but the car ran fine and no lights were on, my mechanic said its ok as well...my question here is that is it possible that the way my GS-R consumes gas might be because of the different ECU
if so what shall i do? how do i check what kind of ECU i have?