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02'-06' Avalanche Owners....How's YOUR Gas Mileage?

I haven?t calculated hiway mpg, but it isn?t too bad......TBH, I didn?t buy my Ag for mpg.....she gives me the best ride ever, though!
 
No matter where I go or how I drive it, I average 14.5 mpg per tankful at best, 13.5 at worst in my '07 5.3l 4x4. The big, wide tires are mostly to blame. But, like others have said, if I was concerned about MPG I wouldn't be driving an Avy.
 
She's stock and barely gets 12mpgs tuned with rpms barely going to 3k around town and less if I'm above 55 on the highway.
Suppose this is the only thing I'm not liking about my avy.
 
The best so far....19 on a 100 mile round trip... but fuelly says my avg. is 13.7 but I haven't owned it long..Since 12/23/20
2013 2WD LTZ Black Diamond
Yikes sorry, posted wrong year Avy....
 
Tacocat, I don't think you are alone with the 12 + - MPG. I used to get about 570 miles per tank (19 mpg) when it was new with stock tires and doing 70mph for 800 miles one way trips. Dropped to to 440-450 (16-17 mpg) running around town.
Now at 220K miles, 31 inch AT tires, crappy stock 373 gears , a rack on top with spare tire, and wooden sliding boxes w/tools in the bed, saddle bags full of recovery stuff, water, oil, etc. Though 4 adults inside and I am darn near maxed on on the GVR. I am lucky to get 360 miles per tank. I should've have looked harder for the 2500.
 
I filled the tank on my 2003 Z-66 today.

The tank was pretty much empty and the driving had been pretty normal.

I got 14.71 MPG and remember thinking that was a pretty good reading.

It's all relative, I suppose.

:) (y)
 
My last tank...14.897 and my computer said 14.8... It seems like I have a good MPG like this one and then the next one is 13ish I fill the same way?. Ahh; I guess that is why there is an avg.mpg lol
 
Id
Tacocat, I don't think you are alone with the 12 + - MPG. I used to get about 570 miles per tank (19 mpg) when it was new with stock tires and doing 70mph for 800 miles one way trips. Dropped to to 440-450 (16-17 mpg) running around town.
Now at 220K miles, 31 inch AT tires, crappy stock 373 gears , a rack on top with spare tire, and wooden sliding boxes w/tools in the bed, saddle bags full of recovery stuff, water, oil, etc. Though 4 adults inside and I am darn near maxed on on the GVR. I am lucky to get 360 miles per tank. I should've have looked harder for the 2500.
I'd kill for 17-19mpg 😆
I'm running stock rims and tires sizes, don't store much of anything inside the saddlebags or bed, just the understand speaker box, keep it tuned up, oil maintained and coolant clean and am about 12-14 around town. The hwy mpg isn't much better.
Not sure what else I can do except stripping the seats and panels.
I know it's a heavy truck and made for highway trips but have to believe theirs a way to make it more fuel efficient around town. A custom program for the ecm or a daughter board maybe?
With the extensive increase in gas prices, I know we're all feeling it.
 
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04 with a 6inch lift and 35's and the best I get is 15mpg hwy. and around 10 in the city. I have a 2000 Silverado 3/4 ton with a 6.0 that gets 20Hwy/15city. It sucks but I love the AV.
 
For us Canadians, over 16K km of ownership now, consistently: 14.2l/00. All highway, stock tire size, 3.73 gears, full synthetic oil. Never changes: 14.2 (I force myself to use a light right foot, though 😂)
 
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I did an experiment yesterday during a long drive. At 55 mph with no wind and mostly flat ground (some small hills). I went 111.6 miles off of 4.254 gallons of gas. That is 26.23 MPG!!! I had a light load in the box (suitcase, smalll toolbox, winter survival kit, and a few other small things). This is by far the best I have ever done, by about 7.5 MPG. The next leg of the trip I bumped it up to 60 MPH. I dropped to about 20 MPG. Then I bumped it up to 75 MPH and got about 15.5. Its amazing what slowing down a little does for mileage. What is the best you guys have gotten? I had never gotten above 19. I have also never driven less than 60 MPH for any amount of time though.
Good morning all new member here. I have a 04 Z66 and was wondering if anyone has put in a performance chip? What was the outcome? Trying to boost my mpg.
 
I don't think they have "chips" like in the old days.

You CAN have an upgraded "tune" put in the computer, though.
 
Good morning all new member here. I have a 04 Z66 and was wondering if anyone has put in a performance chip? What was the outcome? Trying to boost my mpg.
Realistically speaking, unless you're willing to gut performance so that it can prevent you from opening up the throttle, there's not a lot to gain in the mpg department. If anything, there's a placebo effect there that's getting you to hypermile the truck.


you can surely lean out the mixture a bit, but the amount of fuel is in relation to the throttle position. Seeing as your foot also controls the throttle.. well.. im really not certain the gains from a tune itself on a 1st gen is going to net you anything crazy. None of us want to drive it like a prius that cant get out of it's own way, but sometimes that's what it takes.

Now, if you have a lead foot and need the help of a computer, well, i guess it's something to look into. Just dont believe any magic bullet. If it's doing something it will effect performance.

The absolute best i've gotten in my tahoe is 16.3 mpg thus far. With an overall average closer to 15. The avalanche is a bit larger,so i'd be tempering your expectations with these as a best case scenario. These numbers are calculated. Not from a computer (if mine had one). https://www.fuelly.com/car/chevrolet/tahoe/2001/raekal/1090838

The original average when i bought it a few months back was 13.7 mpg. Between a set of new plugs and running injector cleaner in the fuel i've bumped it up a couple. I'd highly recommend running a quality fuel additive cleaner into a few tanks of gas. Check your plugs for wear. Mine were original at 117k and the electrode was mostly gone.


In order to get to the higher numbers in this thread, you're unfortunately going to have to get a newer avalanche. They're that much more efficient with the AFM system, but that comes at a cost. Most of the guys running range plugins are doing so with newer trucks to disable the AFM system to save themselves future headache rather than improving gas mileage. If anything, they're losing a bit in the process.
 
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I got 50 MPG the other day coming down a long grade with a tail wind and going with the rotation of the Earth...
Where you drafting an 18 wheeler or not?
 
Yes, I was third in line in the convoy...
 
10-4 Rubber Duck!
 
I also crouched real low in the seat to help with the aerodynamics
 
Randy never said what the mileage was going up the mountain :laugh:
 
The app on my phone doesn't measure when it goes negative..:confused:
 
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In other words that's when it changes to GPM.. But it does it magnificently, especially pulling a load..
 
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