Actual MPG differing from instrument average
 

I've been manually checking MPG, when I first drove it home after I bought my H2 which was nearly all highway I managed about 14.5 mpg, pretty good, but in town I'm getting about 8.5 mpg at best all city driving. Setting trip odometer and last fill up I used 7 gallons of fuel and drove 58.3 miles. Instrument average shows 10.8 mpg. I was expecting to hit at least 10 mpg in town. Most of my driving lately has been local stop and go though. Most of my driving lately on this last tank was 35mph, still I wasn't expecting it to drop below 10mpg. I'm going to drive it for a week and check again next fill up and see what the results are.

My range on the computer always shows under 300 miles when fully fueled too, I take it it's using the average mpg as a basis for that but even with 10mpg x 32gal should be 320 on the range indicator. Last fill up it only showed 270 miles range.

I never get 10 mpg in town. 8 is more like it. I quit worrying about MPG, I drive it and fill the tank as needed. I do find the instrument reading fairly accurate.

Exactly ....
My Average MPG always read ... LTYW
Less than you want
So I quit worrying and just filling the tank

Ok. It's not bad enough for me to sell it and get a Prius, :D. Since they state 10-14 I thought maybe I had a problem then again my Expedition is supposed to get 12-16, but it's really like 10-14 and I think the Hummer managed the same as the Expedition on highway but it might be a little worse in town. So it's really like 8-14mpg. My instant eco indicator is pegged at 10.8, but I'm just driving in town right now, off about 2 mpg. I haven't managed 10.8 yet but last couple of fill ups it's 35mph or less stop and go. Maybe if you drive on faster roads, up to 45-50mph it might hit 10mpg.

I cleaned out the air filter, there were barely seeds and bits inside. Had to clean the radiator grills out too when I got it. Someone had some fun. Hope none got sucked up into the intake. The rubber gasket on the filter looked pretty good but it's probably time for a new one.

I forgot there was a screen there too, so it would just be small very small bits if they did make it past, probably nothing harmful.

I dont have actual mpg on my 06
I only use Avg mpg to identify a problem . Like once one of the spark plug wire was broken and the mpg drop to 8 mpg avg

I guess it's called average mpg, there's also instant eco, but if I'm checking the actual mpg after fill up that's probably not a good way to compare since it's taking more miles into consideration with the average onboard gauge. Unless I go thru 3 or 4 tanks at 8.5mpg and it's still at 10.8 with the onboard gauge, I don't know how many miles it's taking into the average for its calculation. Has anyone seen their average mpg indicator less than 10.8?

mine is mostly city driving and it shows 8.4 MPG.
engine is strong and no stumbles and throttle body and MAF are clean so is the air filter. plugs looked fine when I pulled them. but I do have 207k miles on the truck.

I'd venture to guess that almost all who do only short city driving trips on average have seen theirs show and average below 10.8.... That is unless they are very very light footed (hard to do as it takes a bit of grunt to get and keep these moving at a reasonable pace) or maybe put even smaller tires than stock with street tread on or something. Around town only driving mine has shown an average of around 10.5. It is dropping now though and likely will drop under 10 as I just put on new wheels with 37" x 13.5" MT tires which is significantly larger than stock.