Something is wrong, however it depends on where/how you drive, in NYC i avg around 13, since i've moved to CT it's more like 17.0 (city driving).
19 is the most I have seen on the highway. (2005 4.8is)

i drive all street mostley here in miami very rare that i get on highway and traffic does suck alot.. also i have been a little heavy since putting the x pipe but the diffrence was 10.6 without x pipe and now 10.0 with x pipe. i was thinking about getting some fuel cleaner and some other crap thats suppose to help. also was thinkin of putting a stage2 intake as thats suppose to help.. but yea. also tire pressure does it make that big a diffence i have not checked them at all ever lol they look full lol. so after every one comment im thinking i need to change some stuff. and the engine is the m62 4.4:dunno:

it does sound good lol. i have a habbit now of reving it every time i turn it on lol my girl says it sounds like i have a challenger outside lol

so you have seen yours go that low before?

no same route every day. work, home, food, gas... but it has been like this since i got it in november. just had to ask as gas is getting pricey 10 to the gallon is kind of crazy

Doesn't seem like much is wrong considering that the display also shows the average speed under 13 mph.

Calculate it on full tanks to get a more accurate reading than short intervals on the OBC.

Doesn't "Consumpt." in the display mean consumption, which is usually liters/100km? Mileage is the inverse of consumption. I guess either way 10.0 is an unusual value as 10 liters/100km is way to good.

my experience is that the on board computer lies about economy, you have to do your own calculations

ive tried and its worse lol

x2 on changing the O2 sensors. Those effect A/F ratio and resulting gas mileage will plummet if not working correctly.

My 4.4 has about 106K miles....totally stock engine (original plugs, O2 sensors, etc) and I'm seeing an average of 16pmg in heavy traffic. And I have a lead foot. My MPG only drops below that if I'm in hilly terrain or really bad winter weather.