• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

Come Inside And Vote On MPG!!


Full Member
Oct 11, 2002
NYC / Long Island
Just wondering the average highway MPG. I have a Z71 and I can't seem to get a pinch over 16 MPG. I usually drive with 4 people in the truck and cruise at about 75, but even a few times when the truck was lightened up I seem to only have gotten a bit better.

Around town I am in the 14 range.

Thanks for your votes!
My first roadtrip, I averaged nearly 19.3 MPG. Now that I have gotten more accustomed to how she handles and likes to be man-handled, roadtrip mileage is more in the 17.85 - 18.35 range. I voted in 18 - 18.9.

Now that I am HPPIII tuned and have the Magnaflow exhaust, I will be closely watching my mileage on our Minnesota-Texas-Minnesota roadtrip. Speed should be a constant 72 start to finish. 1135 miles each way. That should boost my average miles per hour!

Speaking of which. Post YOUR average miles per hour. Mine: 12414 miles / 344.7 hours = 36.0139 MPH. If you are unaware of how to get your hours, turn off your truck and press and hold the trip meter reset stalk.

I'm usually just hauling me, myself, and I.......nothing heavy in the back.......get pretty good mileage. ?;D I voted 18 - 18.9 (highway)?(y)
I cannot vote as I tend to drive faster.......... >:D
A benefit of the wife driving the Av is that we don't put a lot of miles on it. But on the other hand, she drives mostly around town, so we get anywhere from 12-14 mpg on average. :(
Only problem is...
folks like me with the 8.1 will skew the poll results! ;)

Seven :cool:
16.5 mpg here - some highway but mostly city. I'll have to let you know what we get after logging on 3000 highway miles this holiday season ;D.
I am at 14 in town and 15.5-16.5 on the highwy. How does anyone drive these rigs less than 75-80 MPH??

No Tractman, i don't think so, we like big AV's and we don't waste time going from point A to B >:D
Usually average 18.8-19.2, but that is strictly highway driving usually at night with no traffic and A/C on half the time..
Last trip to Mobile AL. got in a hurry and cruise was set at 88 most of the way(except when the valentine one was screaming or the cb warned forehand of impending trouble ahead with lights on top) and mileage dropped down to 17.3 on the trip down. OOOPPPS went back and checked mileage log. the 17.3 was in high winds and thunderstorms. that highspeed trip dropped down to 16.8 the worse ever that i logged in, but 3 hours and 10 minutes to Dauphine Island exit went by quick.........From Lafayette LA.
I voted for the 17-17.9 range...I don't have any hard core facts to support this...but with the cat-back exhaust..and FiPK...I should be putting out a more than average mpg's..... :B:
I'm getting from 17 to 18 on the highway. When I pulled an enclosed trailer total weight 6200 Lbs or so I averaged 12 mpg which I thought was pretty good considering what I was pulling.

I didn't buy the Av for mileage anyway, but it gets better than my Super Duty Diesel did.

Silver_TT said:
What kind of mileage do you 8.1ers get?

I never really tried to estimate my mpg before all the mods, but I can tell that they have helped. I can get up to 13 mpg on the interstate and about 12 around town, if I keep my foot out of it. Even pullling a trailer, I get about 11.5 mpg. Not too bad for the Behemoth!

Living in the Dallas area, it's almost all highway driving, LoL ! My z-66 pretty much stays pegged at 18 mpg. Does the magnaflow or k&n filter truly help with mileage? I'm thinking I should b pretty happy with what I get. And thanks for the trip on average miles, Jamie!
my driveing is a combo of city /hiway
I usually get 18 plus and over 20 if it is straight hiway.
I guess I am one of the lucky ones but I really don't drive it hard :B:
txavatar said:
Living in the Dallas area, it's almost all highway driving, LoL ! ?My z-66 pretty much stays pegged at 18 mpg. ?Does the magnaflow or k&n filter truly help with mileage? I'm thinking I should b pretty happy with what I get. ?And thanks for the trip on average miles, Jamie!
Exhaust, filter, and header mods..should increase your figure....you should see more pennies saved at the pump...assuming you drive it the same as you did prior to modding the above forementioned...it could be a task....once you hear the exhaust note...it makes you want more... >:D :B:
Has anyone noticed a mileage increase this winter. I keep reading where cold air improves fuel mileage and it don't get much colder than this.
Mac: me, Nascar and WVAV all filled up in cambridge after the cruise we got 13.5. 16, and 17.5 respectfully...but mine are skewed because I had the kis in the truck keeping warmm at whitesides and all the time at the ampitheater, will get a good idea on the flat going to Cleveland in a couple weeks...see ya there :D
Got 20mpg driving between 75 and 80 mph on I75. :)
14 mpg around town driving. I noticed it drops to about 13mpg without the hard tops in place.
15 mpg towing camper approx. 3500 lbs. Just put on flow master 50 and have UPD air box on the way, see how it affects mpg.
The crappy :6: winter gas here has dropped my milage. :7: I do combo 70/30 hwy/city driving and lately I can't get over 15 mpg combined :-[. It seems I need a strong tail wind and downhill in the springtime to get over 17 mpg.

Truckman :B: