Trip MPG on recent trip.
 

Could not find a tread to attach MPG to. 5400 miles from St. Louis to Sacramento. Then 3 trips back and forth to Ojai and return to St. Louis from Sacramento. Drove like a dream. I averaged 21.1 at 70 MPH until I loaded it down with 2000 pounds of carpentry tools. It then went to 19.6 at 65 MPH, I took a photo of the gage after a refill and it said 530 miles to next fill-up! Don't know how to post the photo as some folks won't believe without seeing. The drive was fantastic! My last post was on the no oil consumption at all. Great vehicle for long hauls. No complaints at all. Everything worked flawlessly. only complaint I still have is how the dealership treated me after the sale (Legal Robbery). And I'm not done with them yet. If anybody wants to see the gage picture let me know here. I'll figure out how to post it.

GunnyV to attach a picture, you use the Manage attachment button a little bit further down the rely screen page... the picture attached to this message...
when you click manage attachments a pop up window will give you the option to browse your computer for the attachment of your choosing...

Well, I believe you! Our '10 Suburban has topped 20 mpg several times, with the best being 21.6 mpg (drove all the way from Albuquerque to SLC on one tank!), albeit that was nearly all 2-lane highways with speeds from 55-68 or so.

These trucks get remarkably good mpg for such big, comfortable vehicles.

What grade of gasoline are you using and do you know how much alcohol it contains ?
The octane rating should not impact MPG but the amount of alcohol will, most stations have 10% ethanol but can go up to 15 or 20 I believe...
straight gas or marine grade will yield you best of both worlds, MPG and power...:cool:

Every Gas Station was different, most was with 10% ethanol. Some still had ethanol but were below 87 octane. I did not use those. Just returned again and another 4500 on the Tahoe (07/LT0/4x4. This time it was all about speed. 85 in the states you could go 80, 75 in the states you can go 70. Passing some like the were barely moving. Nevada and Idaho I believe are 80 MPH. As far as MPG it went down but not much. Since this trip was all about speed with no worries about Consumption. At the end I used 107 gallons at full speed and 97 gallons on the economy trip in October. Missouri had the most irritating traffic I've ever seen. The big trucks pull into the passing lane to pass other big trucks and slowly pass them over the next mile or two. So you are boxed in for 3-5 minutes while they ooze along. But states with 80 speed limits the big trucks still only go 70 and stay in the right lanes. Clear sailing for me to cruise by like a rocket at 85. Only Missouri on my travels on HWY 80 were bad. I took 70 back to St.Louis in October and the sign should have said Road Work next 2000 miles, the color orange is still am imprinted on my Retina's. So I took 80 from Sacramento home this time. Only 2 work zones and did not have to slow down for them. Lucky me that it was between storms and roads were fine. I only had one problem and it was my own fault. Changed air filter and let loose a lot of dust into the area the MAF is and did not correct it so at the top on the Reno grade truck got sluggish at high-altitude. Stopped and got MAF stuff and cleaned real good. Fixed sluggishness and back to full engine power. I still got around 17-18 MPG even going at little above speed limits. Got oil changed and front brake job at Gold Rush Chevrolet. Got 10% Military discount. Every little bit helps. 305$ for brakes (Original equipment they told me). 39$ for oil change. Only have IPhone. Don't have home computer. can't add photographs. No oil consumption YET, I hate saying it that way but us with this year and model know it will come and when it does Chevrolet will do nothing.

At 60mph I get 24+ around 67-68 I get 22+ at 70-75 I get 20-22,
My ride is a 2008 LT 5.3L 3LT 3:73 gears with 1030hours and 74K miles. 35psi in tires on Mich mx2's new.
Compared to my 2003 Denali its been like a pay raise. The denali got 15mpg no matter what I did. 11-12 combined. It was a 6.0l 3:43 geared AWD.

2012 Suburban 1500 LT with Mastercraft Courser HSX Tour tires at 33 PSI. I am getting HORRIBLE fuel economy. We just bought this thing about 2 weeks ago and our first tank averaged 11.8 mpg (manual calc, not the DIC). So it seems clear something is very wrong because were getting terrible economy again on the second tank!

WHAT IS YOUR SECRET???

I have 3:73 gears 2008 Michelin tires aired to 37lbs cold. 5.3l 2wd Between manual and dic it is correct.