Looking for suggestions on excessive fuel consumption. 2006 GU IV TD42Ti wagon 140k odo about 3t kerb weight, 33" muddies, 3" lift, roofrack, etc. 3" exhaust, airbox 90mm pvc lid mod with K&N, boost 14psi, advanced injector pump slightly, compensator pin at max position, starwheel adjusted slightly, egr mod, butterfly removed in inlet piping, pre turbo EGT max 650, usually 0 to 500 normal driving, standard HT18, std intercooler and piping, minor rattle/knock on cold start up at idle, fairly clean tune, minimal soot off boost. 16L/100km max. Best is 15L/100. Mostly highway and rural driving. Running 2 stroke oil also. Any suggestions? Thinking maybe need more advance on injector pump but already getting knock as mentioned.