Hi Dazza, I've got a 2008 ST-x Navara that's done 70,000 klm. I'm getting 12 ltr/100 klm around town and 18ltr/100 klm when towing a 19' van. The truck is standard. It's having a service today and I spoke to my mechanic about fuel economy. I don't think I'm getting enough klm/ltr. His advice is...