Fuel Range and MPG on 5.3

Ryan Catanese · February 22, 2020

Hello all, first time poster here. First, I know the MPG issue has probably been brought up many times over so I apologize, and I'll try not to be repetitive to anything that may have already been talked about in the past.

The issue that I'm having is bad gas mileage. Right now we're averaging around 12mpg and it's mostly city driving. I don't have a lead foot, I've been keeping the info panel on the instant mileage screen to watch my driving even further. I will add, we just purchased this truck last Saturday so it's almost a full week. It's still on the same tank of gas that the dealership filled it up with. There's a little over 200 miles on it, but the thing I found most confusing is right as we were leaving the dealership with a fresh full tank of gas, I noticed the Fuel Range screen said 230 miles. I figured this had to be some sort of malfunction since it was just fueled up and only had 17 miles on it so I just ignored it. Now, we're right around 210 miles and at 1/4 tank left so obviously the Fuel Range was wrong by the way it's looking. So far the best mileage I've seen was 15mpg and that was on the expressway so here I am looking to find some answers or similar experiences.

More info on the truck, it's a

2020 Silverado RST with Z71 package

Crew Cab short box

5.3L with 3.23 gears

8 speed transmission

Stock 20" wheels

Thanks in advance for any help, and my apologies again if this has been answered before. Thank you.

redwngr · February 22, 2020

Fuel range is base on 'recent' mileage, so if the mileage that was 'recent' when it was filled was crappy, the estimated range will be low.

Similarly if you've been running a lot of steady speed at 55 mph or so it will have reasonably good 'recent' mileage. fill it then and the 'range' estimate will be a bunch higher.

None of them get good mileage when doing a lot of city driving with constant accelerating/decelerating and starts/stops.

Steady speeds will always give better mileage.

High speeds will increase aero loads, so typical 2 lane highway cruise will give better mileage than typical 'freeway' cruise.

flyingfool · February 22, 2020

there are about three average settings for mpg in the DIC, look on youtube how to access them, use the average mpg under the odometer setting, seems to be the most accurate, but my fuel range is always off by about 30 miles. it's only accurate on full tank and all highway miles

Ryan Catanese · February 22, 2020

Thanks for the replies. I appreciate it. I'll keep an eye on everything and go from there. I've figured it's too early to really tell, but figured I would ask around just to be sure.

Buellx72 · February 22, 2020

I've had my 2020 Sierra SLT Crew Cab 4x4 5.3L for about 2 weeks and have 700 miles on the odometer. I drive mostly rural two lane highway and have been in 2 high for most of this. I'm getting close to 18 MPG and my math is close to what the computer says.

Edited February 22, 2020 by Buellx72
Add engine size.

newdude · February 22, 2020

13 hours ago, Ryan Catanese said:

Hello all, first time poster here. First, I know the MPG issue has probably been brought up many times over so I apologize, and I'll try not to be repetitive to anything that may have already been talked about in the past.

The issue that I'm having is bad gas mileage. Right now we're averaging around 12mpg and it's mostly city driving. I don't have a lead foot, I've been keeping the info panel on the instant mileage screen to watch my driving even further. I will add, we just purchased this truck last Saturday so it's almost a full week. It's still on the same tank of gas that the dealership filled it up with. There's a little over 200 miles on it, but the thing I found most confusing is right as we were leaving the dealership with a fresh full tank of gas, I noticed the Fuel Range screen said 230 miles. I figured this had to be some sort of malfunction since it was just fueled up and only had 17 miles on it so I just ignored it. Now, we're right around 210 miles and at 1/4 tank left so obviously the Fuel Range was wrong by the way it's looking. So far the best mileage I've seen was 15mpg and that was on the expressway so here I am looking to find some answers or similar experiences.

More info on the truck, it's a

2020 Silverado RST with Z71 package

Crew Cab short box

5.3L with 3.23 gears

8 speed transmission

Stock 20" wheels

Thanks in advance for any help, and my apologies again if this has been answered before. Thank you.

I've bolded the biggest reason for your MPG.

Ryan Catanese · February 22, 2020

I know the city driving will be lower mpg's, but according to GM it's suppose to get 16mpg during city. I just added a tonneau cover yesterday so I figure that will help some too. My car before this was a 17' Camaro and that thing was pretty spot on from what GM claimed the mpg's would be. Overall, I love the truck and the payment difference and insurance savings will help offset the cost of fuel lol. So not complaining really, just wanted to be sure it was pretty much average with other truck owners. I did a little searching around and was seeing others getting higher mpg's so that's what peaked my curiosity.

Again, thanks to everyone for taking the time to reply. Much appreciated.

2016 Sierra Owner · February 22, 2020

Unfortunately the use of remote start will drop the fuel mileage reading like a rock as well. It's happened in my 14,16, and 20 so far.

Ryan Catanese · February 22, 2020

That makes a ton of sense now because we’ve been using the remote start everyday. We live in Michigan so the weather likes to wait until right before spring to get freezing cold. I have noticed that when I shut the truck off it’ll read higher avg mpg say 12.8, and after getting in after letting it run from remote start it’s usually less like 12.4 or 12.6.

swathdiver · February 22, 2020

15 hours ago, Ryan Catanese said:

The issue that I'm having is bad gas mileage. Right now we're averaging around 12mpg and it's mostly city driving.

...I will add, we just purchased this truck last Saturday so it's almost a full week. It's still on the same tank of gas that the dealership filled it up with.

Unless you see fuel on the ground or smell it real heavy like, pay it no mind until the motor gets broke in. Couple tanks of fuel at least.

You fellas have newer engines than mine which burns 1.25 gallons of gasoline for remote starts on each 31 gallon tank of fuel on average. Nearly all starts are remote starts.

AlaskaTB · February 22, 2020

I have a 2020 Custom Trail Boss, 5.3 and 6 speed and 3.42 rear with 2200 miles. Changed tires to firestone winter force studded. Living in Alaska and I have a newborn so I am warming the truck up with remote start every time. Usually about 10 min of idle before I drive off.

I am about 50/50 city and hwy driving. My milage is 17.5 mpg for the 2,000 miles I have on this truck. I don't drive faster than 65 and most of the time its at 60 mph. On flat road at 60 mph I can get 23 mpg easily. Most of my highway driving with a few hills mixed in comes to 21 mpg average.

This is hand calculated, when compared to the truck info screen my millage is always within 3%. I have been very impressed how accurate the screen says my millage is.

I expect to see a loss in milage when I put back on the duratrack tires. They weigh 7 more pounds per tire and have a much more aggressive tread.

So far I have been very pleased with the millage.