What's everyone getting per gallon out of their 5.3?

I have a 2006 crew cab z71 and I get 14 1/2 mpg no matter what I do. 285-70-17 tires.
I hear of people getting 18mpg with same set up and I just don't believe it.
What say you?

I got a 99 z71 with a 5.3. I get 14.5-15. Like you said it don't matter how you drive it. You could drive it off a cliff an get 14.5-15 on the way to the ground.

I got 13-14 outta my old sierra with the 5.3 and it was lifted 9" with 37" super swampers.

Had to have been pre-ethanol

Its been bout 6 years ago i guess since i sold it.

Mine is a 2012 model and it gets 18 miles per gallon. Prior to that I had a 2009 model and it would get 17.5 miles per gallon. Fairly good amount is highway miles though.

2004 has averaged 16.3 on the life of the truck....I can get 20-22 on the interstate on long hauls.....14-15 around here stop and go.

2006 crew z71

Get 16-18 depending on how I drive it.

Same here had an 03 z71 with the 5.3 9 inch lift and 37 inch mud grapplers. Getting right around 14

'05 Sierra crew Z71. 5.3 4:10 gears. 14-15 mpg.

My 2012 Sierra Z60 4X4 gets 16 mpg. I have a K&N Cold Air Intake and a Gibson Metal Mulitia Exhaust System I put on the truck and it improved my gas mileage by .1 mpg. Truck is a whole lot funner to drive though.

2001 Z71 5.3 330,000 miles still gets 17 mpg. I have stock size tires,265/75R16

Im getting right at 17.5 mpg in my 2010 (with winter blend fuel). Spring and summer time I get about 18.5

Avalanche 1500 Z71 Pre Ethanol 17-19 Now 14 No matter what. Stupid Ethanol cost more and My truck use more how is that better. Same For Trans am Glad its a 6 speed 5.7 in it can still squeeze out 22mpgs if I keep my foot out of it.

2007 Sierra 4x4 with 122,000 miles.

Old tires: Goodyear Eagles 255-70-20-- 15.8 average for life of the truck (13 or so around town, 18-19 hwy)

New Tires for the past 5,000 miles: Nitto Terra Grapplers 260-70-20 getting about 2 mpg less on average, but I haven't been doing nearly as much highway driving since November in my truck, so I'm sure that has tweaked the mileage a good bit.

About where my 09 is. I have found that diff gas can make a HUGE diff, and some of the cheapest can sometimes be the best!

2013 Chevrolet Z71 extended cab getting about 14.3 around town might hit 20 on interstate. It has factory 18" tires and 6 speed auto. I had 2011 single cab Z71 it did a little better than this one same set up.

I have a 2012 4 door crew cab z-71 and My fuel average on my truck is about 15.8. i am sure it might get a little better if a drove on the interstate all the time. But i don't.

2001 ext cab z71 5.3 3.73 285 10 ply mud tires in town 13.5-16 towing the ranger @ 70 mph 10 mpg. Sent computer to black bear performance that really woke up the truck I highly recommend it for all you 4.8 5.3 6.0 truck people.

Not a truck but is a 5.3. 2008 burb, 4x4 loaded with 6 adults and gear to Mobile and back, 19.4 mpg