2001 3 door sports Auto Grand Vitara excessive fuel useage 150000klms good cond

Hi.....Daz...... what do you call excessive? Two things........ firstly you must make sure your vehicle is in optimum running condition, so you need to check and renew if required, things like air and fuel filters, plugs, check spark plug hi tension leads, coils and wiring harnesses, timing, injectors , engine management systems....... checking also for fuel leaks around pipes and unions and the tank. If all ok, then you must carry out a controlled fuel consumption check. fill your tank brimm full......note the mileage and drive the vehicle normally, do not make an effort to drive economicly, drive as you would daily for a couple hundred kms, return to tha same garage and same pump, brim the tank and note the mileage and litres filled and do a calculation of how many kms per litre... I think you might be surprised........... bear in mind that the vehicle has done in excess of 150000 k and as the engine gets older will loose some fuel efficciency..... its called wear and tear..... hope this helps.... Happy Christmas.......... Steve Botswana