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Avalanche? More like Avtofillupeveryfewdays

D

Davydave

Full Member
Joined
Jul 24, 2018
Messages
10
Its a stock 04 2500 8.1
I get 11.7-12 mpg  and 15 sometimes 16 mpg on those nice toll roads

What can i do to improve fuel economy?
 
First welcome to the website!

Unfortunately you are getting about par MPG for a 2500 AV. It has never been known for good gas mileage. The best thing about the 8.1 is it's towing/hauling capabilities,
about the only thing you can do is decide if you need all that capacity. (If not sell it for a 1500 5.3 Av but even then don't expect much improvement in MPG.)
The AV is a 6,000- 7,000 LB vehicle with the aerodynamics of a brick so it's not an economy vehicle.
The best you can do with any AV is to drive it like an old geezer with slow starts, slow stops and avoid stop and go traffic when possible. Also use cruise control and keep speed below 70 or so. Then consider things like proper maintenance and tune-ups, tire size close to stock and properly inflated also no lifts and things to increase weight or drag in the airflow. Don't believe the advertising hype of miracle fuel/oil additives or CAI systems improving MPG too.
When gas prices go up MPG talk is all over this website and many people either sell their AV or buy an economy car or motorcycle as a daily driver to save on fuel costs.
 
Vaeagleav said:
First welcome to the website!

Unfortunately you are getting about par MPG for a 2500 AV. It has never been known for good gas mileage. The best thing about the 8.1 is it's towing/hauling capabilities,
about the only thing you can do is decide if you need all that capacity. (If not sell it for a 1500 5.3 Av but even then don't expect much improvement in MPG.)
The AV is a 6,000- 7,000 LB vehicle with the aerodynamics of a brick so it's not an economy vehicle.
The best you can do with any AV is to drive it like an old geezer with slow starts, slow stops and avoid stop and go traffic when possible. Also use cruise control and keep speed below 70 or so. Then consider things like proper maintenance and tune-ups, tire size close to stock and properly inflated also no lifts and things to increase weight or drag in the airflow. Don't believe the advertising hype of miracle fuel/oil additives or CAI systems improving MPG too.
When gas prices go up MPG talk is all over this website and many people either sell their AV or buy an economy car or motorcycle as a daily driver to save on fuel costs.
Click to expand...

Thanks for the welcome!  I dont think I could sell the avalanche.. the original owner I bought it from almost cried when I drove away.. After a month I can see why, its an amazing truck. bought it with 35000 miles. I drive alot so it seems every few days I drop $70 and its not even empty. But I got it for a good price so everything balances out in the end. oh well.
 
Take a look at the sticker on the glove box door. See if you have GT4 or GT5

GT4 is 3.73 rear gear ratio GT5 is 4.10.

Take a look at tires also for signs of dry rot and cracks

If it's stock and 14 years old and 35,000 miles, it may be time to replace a few items.
 
I met a tuner in the Seattle area that said with a tune, he was getting around 18 to 20 highway iirc, but he had to run 92 on that tune.  And yes, it was for his 2500.
 
That's a interesting statement Wickman, does he have a 2500 AV or Suburban
 
I've never tried 92 octane because it is at least 80 cents more than 87. When I drive on smooth flat land thru Ohio with the windows cracked, the tires aired up to 60 PSI for less roll resistance and the rear window out I can get it up to 17 Mpg.

I also have a straight intake CAI, because the stock one is so restrictive. If you have ever seen a stock 8.1 intake you know what I mean. If I keep it below 2200 RPM and in 4th gear it's OK but if I hit a city it drops back to 8-12. 
 
  I just giggle I let off the gas pedal jumps to 30mpg + on DIC going down hill.
Just touch it starting up hill drops 4mpg. So glade to behind a BBC again.
:love: 496.

No hugs needed. 

 
 
Worse thing is if you happen to get stuck in traffic on the highway because the road is blocked you can sit there and watch the gas gauge out down.  If its running it's sucking up gas, if I'm towing I just pull off to the side of the road and turn it off.
I consider it gallons per hour.
 
wow... and here I go like a month or 2 between fill ups on my regular driving, but when I have to drive more than normal, I fill up every 2-3 weeks. I just keep up on maintenance and listen to her needs.
 
MS03 2500 said:
I've never tried 92 octane because it is at least 80 cents more than 87. When I drive on smooth flat land thru Ohio with the windows cracked, the tires aired up to 60 PSI for less roll resistance and the rear window out I can get it up to 17 Mpg.

I also have a straight intake CAI, because the stock one is so restrictive. If you have ever seen a stock 8.1 intake you know what I mean. If I keep it below 2200 RPM and in 4th gear it's OK but if I hit a city it drops back to 8-12.
Click to expand...
60 PSI ! Wow that seems a little dangerous for a couple mpg.
 
vincev said:
60 PSI ! Wow that seems a little dangerous for a couple mpg.
Click to expand...
Not at all.
The 2500 AV calls for E rated 10-ply tires, which can be inflated to a maximum of 80 PSI.
Even the door sticker shows 80 PSI for the rear tires. LOL...
I never do that, as it makes the ride too rough. I figure that GM assumes you'll have a substantial load in the truck.
 
CarMech1969 said:
Not at all.
The 2500 AV calls for E rated 10-ply tires, which can be inflated to a maximum of 80 PSI.
Even the door sticker shows 80 PSI for the rear tires. LOL...
I never do that, as it makes the ride too rough. I figure that GM assumes you'll have a substantial load in the truck.
Click to expand...

I will pump them up when towing at highway speed. LOL
 
To see if you have the right air in your tires there is a test that I was taught long ago, take a piece of chalk and put two lines on the tread, then roll forward or backward and look at the chalk, if the chalk is gone in the middle it is over inflated, on the outside underinflated, gone, properly inflated.
I run the Avalanche with 65psi all around and the Suburban with my work tools at 65 in front and 75 in the rear, the tires wear flat across and rotate them every 5000 and they wear evenly.
Give that a try and let me know your results.
:)
 
Last edited:
Huh, that's an interesting test. I had a flat in one of my rear tires and went to go air it up with my adorable (now I know) 2 gallon air pump. I opened the driver door.. "60psi front..80psi.. rear.. Holy crap". I went and checked the tire, 80psi max. So, not knowing any better, I tried my best to get it to that level. My compressor could only manage about 55psi.

I had them top off the air in my tires sometime later and the service advisors looked at me weird when I said the sticker said that. They both looked at it, then asked me what I wanted to put in it because they had only put 45psi in them when they installed the set. I told them to put 80 in them because I knew when I came in for a tire rotation they wouldn't pay attention to an unbalanced fill. It definitely rides stiffer Too bad I havent been able to drive it in a month, I was curious how much higher the mpg would creep up with summer gas and inflated tires. I was getting 11.5ish in december. Last I checked It was up to 12.7mpg before i had to park it for this fuel tank fiasco.
 
Vaeagleav said:
First welcome to the website!

Unfortunately you are getting about par MPG for a 2500 AV. It has never been known for good gas mileage. The best thing about the 8.1 is it's towing/hauling capabilities,
about the only thing you can do is decide if you need all that capacity. (If not sell it for a 1500 5.3 Av but even then don't expect much improvement in MPG.)
The AV is a 6,000- 7,000 LB vehicle with the aerodynamics of a brick so it's not an economy vehicle.
The best you can do with any AV is to drive it like an old geezer with slow starts, slow stops and avoid stop and go traffic when possible. Also use cruise control and keep speed below 70 or so. Then consider things like proper maintenance and tune-ups, tire size close to stock and properly inflated also no lifts and things to increase weight or drag in the airflow. Don't believe the advertising hype of miracle fuel/oil additives or CAI systems improving MPG too.
When gas prices go up MPG talk is all over this website and many people either sell their AV or buy an economy car or motorcycle as a daily driver to save on fuel costs.
Click to expand...
I’m fine with mpg I know if I buy a full-size Chevy with a big boy V8 that I don’t care to give her some ole gasoline not to be rude but if you care about mpg buy a Prius of a foreign car I love Gm and I’m proud they gave us the holy grail avalanche
 
Love the truck, hate the mileage. When I hammer it on the highway I love the surprised looks, like “How does something that big jackrabbit that fast?” Then I look at my mpg readout and I remember why. XD
 
BigDav32001 said:
I’m fine with mpg I know if I buy a full-size Chevy with a big boy V8 that I don’t care to give her some ole gasoline not to be rude but if you care about mpg buy a Prius of a foreign car I love Gm and I’m proud they gave us the holy grail avalanche
Click to expand...
I'm in complete agreement... And that is why I have a Chevy Bolt for my daily lol

I live in socal, even with 32 cents a kWh I'm saving $$$ monthly.

My gas savings alone pay for my bad habits :help:
 
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JVZL1 said:
He drives a Duramax now.
Click to expand...
Yeah a few of us 2500 owners went that way including me. GMC oiler 900+ foot pounds torque and a more modern tranny make pulling a 34 foot airstream up a hill a breeze. Down side the ride, I only drove it about 2,000 miles in 3 years. But my AV is not going anywhere
 
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