Gas Mileage

[Stevens03]

I'm getting a solid 13-17mpg out of my 6.2L with 3.73 gears.

 

I believe the mileage people get are weight heavily on geographic location, altitude and many other variables. Its hard to nail down an exact mileage on these trucks. If you live in an area of mild hills and back roads, your gonna see alot worse mileage than someone who lives out west and drives on mostly flat roads. Tires and tire pressure also weigh in on the mileage people see. One set of tires can have a horrible rolling resistance verses another.

 

Its just not something thats an exact science. And quite frankly if your worried about mileage, maybe a truck isn't what you should be driving.

[reidrhollander]

OP: Where do you live, and how do you drive? Also, what motor/transmission?

 

 

Well a lot of things came up in this thread that I guess are going against me. For one I live in Kansas so my highway speed is about 78 MPH so I guess that is probably killing me. And I didn't know you were supposed to reset the economy meter when you fill up, to me that kind of defeats the purpose of an overall fuel economy computer.

 

I have the 5.3. Not sure about the transmission or gears. Whatever comes in a All Terrain edition Sierra is what I have. I guess I need to run the VIN and see what gears I am running.

[txab]

Look for RPO codes in the glove box.

 

GT4 Rear Axle: 3.73 Ratio

GT5 Rear Axle: 4.10 Ratio

GU4 Rear Axle: 3.08 Ratio

GU6 Rear Axle: 3.42 Ratio

 

And yes running 78 mph is going to drop your mileage.

 

I'd still calculate mileage by hand sometime. DIC can be off on some vehicles.

[limpalong]

OP: Where do you live, and how do you drive? Also, what motor/transmission?

 

 

Well a lot of things came up in this thread that I guess are going against me. For one I live in Kansas so my highway speed is about 78 MPH so I guess that is probably killing me. And I didn't know you were supposed to reset the economy meter when you fill up, to me that kind of defeats the purpose of an overall fuel economy computer.

 

I have the 5.3. Not sure about the transmission or gears. Whatever comes in a All Terrain edition Sierra is what I have. I guess I need to run the VIN and see what gears I am running.

 

 

I, also, live in Kansas. Similar truck. 2008, 5.3 afm, 3.73, Z71 4wd. I just turned over 50,000 miles a couple weeks ago.

 

I've found wind makes a huge difference. If I am pushing a headwind, the mileage drops dramatically. I've also found my truck does NOT like the Casey's gas with a little Ethanol in it. I lose a couple mpg if I fill up at a Casey's. I get my best fuel mileage with 87 ocatane... all gasoline.

As others have said, speed kills mileage. I still need to get where I'm going in a reasonable timeframe. So, I don't try to keep it at particularly low speeds. Yet, I don't drive 80 either. It it's a posted 70 mph limit, I'll set my cruise at 74 or so.

I-70, especially between Topeka and Abilene, can get pretty hilly. I try not to allow my truck to downshift. When it does, the rpms will go well over 3,000 and the fuel milege drops accordingly. I have learned where the most severe hills are and will kick out of cruise and "pedal" it over those grades.

I've seen as high as 19 to 22 mpg, traveling nothing but flat interstates in the summer time. Most of my driving is a mix between highway and small town driving. I'll average 15 to 16 on those tanks of fuel.

One of my work associates has a similar truck, only in crew cab configuration. He runs an Escort detector... and needs it!! All he knows start late and make up for it during the commute. It's nothing for him to run 80 to 85 in posted 65 zones. He gets really angry with me when I comment on my mileage. Doesn't seem to understand why his truck does so much worse than mine!!???!!!!!

[DALE#3]

I have a2011 colorado 5.3 z71 4 whl.dr. with 4.10 rears.The rears are killing my mpg.If i keep tach below 2k i get 15 mpg.thats 67 mphr.I can't drive 65 (new song) but have to if worried about$$$.I added cat back mag.#40 exhaust,k+n filter in stock box,custom intake.Now tune coming up.Maybe i'll gain a little with tune?Truck has 2k on odo.I'm bitch'n to gm now about the piss poor only 4.10 rear available on z71 with trailer pkg.They won't do anything i'm trying though.You purchase a truck don't expect fuel economy.But chev does advertise 20 hwy.on full size w/5.3 WTF.Got to be down hill only with back wind?

[tyhuck]

I get 15 - 17 mpg, 90% hwy, averaging about 72mph. But, Im running an 05 with no AFM and a 4 spd. I also live in the woods where wind is not a problem.

[DALE#3]

Not bad alot more mass pushing around than the colorado.rear ratio must be low 3's and a 4.8

[tyhuck]

No, mines a 5.3 but its got a 3.42 gear setup. I wish I had 3.73s though. I like MPG but I like Tq better.

 

 

BTW, Im pretty sure the 5.3 Colorado Z71 was offered with a higher ratio. Im not sure if it was the 3.73 or the 3.42. I just remember it was the 3.something. You could always have a shop regear your truck. Might take a while to recoup anyfuel savings afterwards though.

[KMGZ400]

I get 15 - 17 mpg, 90% hwy, averaging about 72mph. But, Im running an 05 with no AFM and a 4 spd. I also live in the woods where wind is not a problem.

 

 

^^same exact results with my 03 suburban.... it does the best on fuel over my other trucks

[jaslo]

I feel lucky getting 16 mpg with my 01

[rat454]

I have an 09 sierra with 5.3 and 6 spd. I reset my mileage and trip after every fillup. I have about 23k miles on it now and bought it used with 16K. I have found that mileage is greatly affected by the way I drive and the MPG displayed is as much as 1 mpg off from actual. Below are mileage figures that are manually calculated:

 

highway only 70 mph

[rat454]

I have an 09 Sierra crewcab 2wd 5.3 6spd w 3.42 gears. All mpg figures are calculated manually:

 

highway @ 70 mph cruise 20.2

city driving like a grandpa 16.97

highway driving like i want

[DALE#3]

Thinking about trading for a canyon v8 with 3.42 my colorado 4.10 literally sucks.GONNA TAKE BIG HIT ON TRADE.Maybe by a shit box with the money i would lose on trade and keep the miles off of the truck.Trucks got 2k on spedo

[cghbuilder86]

You should certainly reset your MPG Average. When I first bought my used '04 it had 14 on the average. I thought oh great! Because I also drive 35 miles one way to work. But guess what, I average 17-19 mpg hand calculated! I reset my average every fill up, the reason being oil changes, towing my horse trailer, driving in 4x4 (snow) etc. I don't want all that in my average and it takes a while to come back from stuff like that pulling it down. I usually fill up at around 400 miles on a tank. I do drive 95% on a flat highway where the speed limit is 55 mph. It makes for a great enjoyable drive everyday. I also use a very gentle foot, always coasting when I can avoiding the brake and idling. In the cold winter I average around 17 and sometimes 18. In the summer 18-19. In the perfect conditions like spring and fall and extremely gentle driving I have squeezed 20 out of it It is a ext cab z71 5.3 4speed with 3.73 btw.

Speed is also a big factor I find that my truck gets maximum mpg at 45 mph. Of course I can't go that slow but when the roads are empty I'll slow down to about 50 or 53 mph that will help bring a few point on the mileage.

 

I get so tired of the comments saying if you care about gas mileage you shouldn't be driving a truck. It gets under my skin a little bit. If you dive 10 or 20 miles a day maybe its a minor thing to you. But some of us actually drive our trucks. I drive 70-80 miles every day and I'm not willing to drive a car. But I don't want to throw away excess amounts of money in gas either. With gas prices like they are. Mileage always matter.

 

 

I keep seeing people on here claiming they are getting 17-18 on the highway and 14-15 in town. I commute 35 miles each way to work everyday that is all highway and have never reset the fuel economy computer in the 18 months since I bought the truck new. With 80% of my driving on a 4 lane highway it still says I am only getting 14 MPG.

[MaverickZ71]

Greetings to Reid and Limpalong--always glad to meet some fellow KS GM truck owners. I'm from SE KS, currently working in Topeka. I agree that out here, wind conditions and hilly terrain can greatly influence the gas mileage, as can the ethanol content in pump gas these days. On the interstate, I usually set my cruise around 75 mph, but they are talking about raising the speed limit to 75, so that soon may be 80 mph.