
I tried the instant fuel consumption and it seems that its a bit low.

When I'm going 110KPH (3000rpm @ 6th gear) with A/C it says that I'm doing 5L-5.5L per 100KM which is too low, My car is highway rated at 7.9L/100KM (in the UK) and 9.8L/100KM (in the US).
I'm calculating the MPG using the MAF method, is there any way that I can increase its accuracy? I filled the tank before a few hours and gonna see how much Hobdrive calculation differs from the real world.