my 2005 cruiser was great on fuel, doing under 8 litres per 100 km. for some strange reason that has now gone up to 15 litres per 100 ks. all service work done as required. at my last service i put 10w 30 gulf western oil in it. surely that would not cause such a dramatic increase. it is running fine, no problems whatsoever. it has 135000 ks on it. brakes are not binding, it has got me beat.
Get a bottle of fuel injector cleaner & pour it in before refueling. A bottle can be bought from the dealer for $22 IIRC. The one from Toyota is made in Japan and available in two types, one for Petrol & the other for Diesel engines. Otherwise, Liqui-Moly Total Fuel System Cleaner from Supercheap Auto or Repco is another good alternative.
Also, get your oxygen sensors checked (Got my RAV4 diagnosed by the Toyota dealer 2 years ago. Two failed sensors was what caused the abnormally high fuel consumption.)
Thanks ToyotaFreak. I will try injector cleaner first and see how i go. If no improvement i will get it scanned. I would have thought a dash light would have come on if it were a faulty sensor. Thanks so much for your help.
In my case, there was no warning light, the dealer scanned my car and gave me a fault code (I also remember being told that it's rare to have both oxygen sensors fail, as it is usually one or the other.).
I wouldn't get them replaced by the dealer though, they wanted $600 per sensor, excluding labor! I ended up sourcing the Toyota genuine ones from Malaysia which costed me less than half of what the dealer wanted back in Australia.