I get 16 - 18 Miles Per Gallon Highway which would mean you would get 3.5 litres for 100 Km (Check here -
http://hemsidor.torget.se/users/b/bo...ert/conv_e.htm) I have a 5.3 2001 Yukon XL which gets a little less than the Yukon. But I would not trade the ride (Big, bad, etc.) for nothing.