GM 5.3 gas mileage

[deerefan]

I bought a 2011 Z71 4x4 ext cab in December. It has the tow package and 3.42 gears with the 6 spd auto. I have about 5500 miles on it and am averaging 15.8 mpg hand calculated. I find this rather disappointing considering my 97 F150 4x4 ext cab with the 4.6, 4 spd auto and 3.55 gears get 15 flat. Here we are 14 years later and light years ahead in technology and the mileage is basically the same. I can't call GM a liar as it states 15-21 mpg on the sticker and I am getting 15.8 (the computer mpg says 16.3 avg). For comparison, my father has a 2010 avalanche, 2wd 3.42 gears and he is seeing 18-19 mpg. I drive normally, not lead footed. Another thing I noticed is at 62 mph, I am turning the same rpm as my ford. Weird considering my trans has 2 more gears than the ford. Anyone have the same truck? What mpg are you getting?

 

[houstonscott]

I have a 09 Z71 suburban 4x4 with same engine transmission and gearing. I average about 17.5 on the computer over 40K on the truck.

HS

 

[jonyyuma]

Reading your facts is astounding.. My 1973 Chevy 307/ {350 later} had 3 on tree and 3.40 gear. It pulled 15mpg and 14 mpg respectively. Now does your 6 speed include overdrive? Seems like something is missing here, other than does your 4x4 , become a 2wd, or is it maintained ? Btw my Son drives a 97 ford 4x4 same as yours and it does the same mpg with a whole lot of miles on it..

 

[ME83]

That seems off. I had the exact same truck as you except it was a 2005 which only had the 4 spd auto. In the summer I always averaged 17.5 mpg mixed driving, winter dropped usually 2 mpg with the different fuel. I would think you should average 18 to 19 mpg. Highway the truck was always 19-20 mpg up to about 75 mpg, and didn't drop too much doing 85 or so. This was all hand calculated.

 

[LD1]

I bought a 2011 Z71 4x4 ext cab in December. It has the tow package and 3.42 gears with the 6 spd auto. I have about 5500 miles on it and am averaging 15.8 mpg hand calculated. I find this rather disappointing considering my 97 F150 4x4 ext cab with the 4.6, 4 spd auto and 3.55 gears get 15 flat. Here we are 14 years later and light years ahead in technology and the mileage is basically the same. I can't call GM a liar as it states 15-21 mpg on the sticker and I am getting 15.8 (the computer mpg says 16.3 avg). For comparison, my father has a 2010 avalanche, 2wd 3.42 gears and he is seeing 18-19 mpg. I drive normally, not lead footed. Another thing I noticed is at 62 mph, I am turning the same rpm as my ford. Weird considering my trans has 2 more gears than the ford. Anyone have the same truck? What mpg are you getting?

I had an 03 with the 5.3. Not sure on the tranny, 4speed? maybe 5?? and I could get around 16MPG like you. Loaded with a trailer and tractor @ ~6500lbs, I would only get 9-10MPG.

But you are right, I dont think we are getting anywhere with the mileage on these trucks. A lot of it is emissions BS, but I think we could still do better and we are not.

Dad had a 1985 chevy K20. 3/4 ton, 4wd, 3-speed w/ granny, 350 carbureted. And he could get 15MPG. He was utterly disappointed when he traded it (many years ago) for a 1998 dodge w/360 and couldnt do any better. And then again, when he got a 2005 dodge w/hemi and still...14-15MPG. It seems in almost 30 years, there has been NO improvement to MPG. Even with double the gears in the tranny:confused2:

 

[jonyyuma]

Ld1, Yes there has been a bunch of different engines, some of the guys here has gone to nearly straight exhaust and not cats, still not getting the advertized mileage.. I had headers and turbo exhaust on my old 73 and never even raised it 1 mpg. But I do not see how these guys feed those Hemis...?I read comsumer reports and they raised 9 mpg in city?

 

[om21braz]

Here 2007 NBS 5.3 w/ 3.73 & 4 spd. auto gets approx. 15-16mpg average and I have gotten as high as 20 highway alone. In 121,000 miles the average on the computer is 16.9mpg. Almost exactly the same as all models I've had w/ 5.3 eng. regardless of rear end ratio.

 

[tcartwri]

It takes X amount of horsepower to push a 4x4 through the air at any given speed. That required HP is directly proportional to the amount of fuel you use.

Doesn't matter what gearing, what engine, whatever.....

Speed is the enemy for fuel economy with these trucks. Even my Explorer will touch 30mpg if I stay under 50mph, with no head wind, warm air, etc....

Your consumption will go up exponentially with your speed. It is not linear.

 

[dixstir]

maybe to new of a truck mine gets 20-22 hwy (1957 chevy 3 speed overdrive and a 342 rear gear) I think I will keep it but my 2002 gmc 4.8 get around 20 not much dif in all those years.

 

[timswi]

I average around 16mpg with mixed driving..2011 GMC 6.2 6sp 3:42 4x4. I run it pretty hard though, 70+ mph going to work.

On the highway, taking it easy, I can get 19-20 depending.

 

[Soundguy]

my 2000 yukon, with 5.3, and I believe 3.73 rear and auto trans gets about 14mpg, and only uses about 2qts of engine oil per 3000 miles... since new.. and gm says that's normal

no leaks either..

soundguy

 

[psj12]

Obama's new mileage goal for light trucks in 2020 is 51 MPG. LOL

 

[LD1]

Obama's new mileage goal for light trucks in 2020 is 51 MPG. LOL

in 30+ years we have managed to increase 1/2-ton truck MPG 0

How are we going to get to 51mpg in 9 short years:confused2:

I have said before and I'll say it again:

Why dont a mfg come out with a 3.5-4 liter small diesel for these 1/2 tons???

If we can get ~20mpg or better out of diesels twice the size, with 350HP and 750 ft-lbs, lets scale it down a bit. Say...a 4.0L diesel @ ~225HP/475ft-lbs that would get 30mpg+ in a half ton. And it would tow better than the 380HP gassers we have now:thumbsup: I for one would be willing to pay a good bit extra for a 30MPG diesel vs a 15-16MPG gasser.

15mpg gas @ 3.50 per gallon over 100k miles = $23k
30mpg diesel @ $4...."........."......."........"....=$13K

$10k savings in the first 100k miles:thumbsup: I'd jump on board:thumbsup:

 

[Car Doc]

Don't feel bad about your GM none of the new trucks from anyone do well from what I hear some are even worse the Titan or Hemi comes to mind.

IE my 02 Tundra 4.7 v8 4wd gets 15 not loaded and with quite a bit of tailwind if I am lucky and about 10-11 in town.

It will pull a house and rides like a car runs like hot rod but it sure loves gas $80-90 fill ups not uncommon right now.

 

[zzvyb6]

You realize that the gas you are using is now 85% gas and 15% after shave, right? Try putting 40 - 45 psi in the tires and watch the motor switch to 4 cyl mode. Then try to keep it there. There's quite a bit of mileage loss because of the way people accelerate and brake. Pretend there is an egg on the gas pedal and the brake pedal has been sawed off. Then you can get near 20 mpg.

 

[WilliamBos]

my 2000 yukon, with 5.3, and I believe 3.73 rear and auto trans gets about 14mpg, and only uses about 2qts of engine oil per 3000 miles... since new.. and gm says that's normal

no leaks either..

soundguy

My 04 5.3 uses .500ml in 4,200 miles.@ 142000 miles. Seems to be a hit and miss situation.

 

[Soundguy]

speaking of fuel economy.. i hear ford has come out with some small 3.7 or something twin turbo gasser called an eco edge or somthing to that effect. suposed to be a decent pulling truck. havn't seen one.. just heard the hype froma salesman trying to sell me one while I was looking for a trusty 7.3 psd on his lot.

a diesel for a half ton would be nice...

soundguy

 

[Car Doc]

This seems to be the only continent on the planet that small diesels aren't in everything from little kiddy cars to 2 ton trucks.

Toyota has been putting them in their small trucks for 30 years but you cant get one here dumb.

I second the small diesel notion I would have one in a heart beat in a half ton I am in no big hurry anymore to get anywhere money is getting tighter as well.

Go figure we have some of the strictest emissions and use the biggest least fuel efficient engines dumb. :laughing:

 

[WilliamBos]

speaking of fuel economy.. i hear ford has come out with some small 3.7 or something twin turbo gasser called an eco edge or somthing to that effect. suposed to be a decent pulling truck. havn't seen one.. just heard the hype froma salesman trying to sell me one while I was looking for a trusty 7.3 psd on his lot.

a diesel for a half ton would be nice...

soundguy

Ecoboost - Direct injected twin turbo gasser.

I would love a 4.5L Babymax 1500.

 

[HiTechTed]

I'm sure that oil companies and crooked politicians have nothing to do with the lack of MPG increases in the last 30 or so years. Too many people have their hands in it, and they are making too much money to care about changing things.

I'll bet MPG could be at least doubled RIGHT NOW if all the corruption surrounding oil didn't exist. Of course if the mileage of vehicles doubled, the crooks would just double the price of fuel.

I'd also like so see a smaller diesel 1/2 ton truck, that's a good idea.