Horrible MPG, what’s wrong with my truck!

Codeman00 · January 31, 2020

I'm really happy that I read this thread. I have the 2019 Silverado RST Z71 with the 5.3L. I couldn't figure out why my highway MPG was so bad..it was around 18.9-19.1mpg. I used the info posted here and slowed my speed from 78mph to 70mph.

My 95 mile trip (70mph) increased to a whopping 22.3mpg !!

I tried the next 36.2 miles at 72mph and it dropped all the way to 20.4mpg.

I'll keep testing this out but like someone said above...a few mph makes a HUGE difference in gas mileage.

Grumpy Bear · January 31, 2020

14 minutes ago, Codeman00 said:

I'm really happy that I read this thread. I have the 2019 Silverado RST Z71 with the 5.3L. I couldn't figure out why my highway MPG was so bad..it was around 18.9-19.1mpg. I used the info posted here and slowed my speed from 78mph to 70mph.

My 95 mile trip (70mph) increased to a whopping 22.3mpg !!

I tried the next 36.2 miles at 72mph and it dropped all the way to 20.4mpg.

I'll keep testing this out but like someone said above...a few mph makes a HUGE difference in gas mileage.

These 'Crappy Fuel Mileage" threads are almost as common as oil debate threads.

It isn't rocket science. Yet every time I've mentioned speed in connection with mpg I get run out on a rail.

:crackup:

People just insist on peeing the electric fence for themselves before they can make the connection.

:idiot:

Edited January 31, 2020 by Grumpy Bear

DogMom · January 31, 2020

I'm really happy that I read this thread. I have the 2019 Silverado RST Z71 with the 5.3L. I couldn't figure out why my highway MPG was so bad..it was around 18.9-19.1mpg. I used the info posted here and slowed my speed from 78mph to 70mph.

My 95 mile trip (70mph) increased to a whopping 22.3mpg !!
I tried the next 36.2 miles at 72mph and it dropped all the way to 20.4mpg.

I'll keep testing this out but like someone said above...a few mph makes a HUGE difference in gas mileage.

Ingesting. I have the same truck and average 17.7 Highway going 60-65mph. Maybe 70 is the sweet spot like it is for my husbands 2500 duramax.

Sent from my SM-G965U using Tapatalk

diyer2 · January 31, 2020

Eye see lots of lip service due to the lack of common sense.

jamesonjc · January 31, 2020

On 1/19/2020 at 9:25 AM, BlaineBug said:

Increased emissions standards are a killer. My Mother had a 1982 Volkswagen Jetta non-turbo Diesel that got close to 40 mpg city. Where have all of the supposed "economic" vehicles went? That car was less than $10,000 when it was bought brand new as well. You can't find anything close to it today.

You can get a malibu for under 20k with discounts and with discounts maybe get a spark or sonic in that range. Very fuel efficient, very small.

1982 was almost 40 years ago too - so..... Thats like saying in the 80's my dad got a willys for $150 - give me the model with the tube radio i dont care.....

Edited January 31, 2020 by jamesonjc

jamesonjc · January 31, 2020

I have also had three silverados in a row - all v8's here is the mileage

2016 lt double cab - leased turned in with 24k miles on it in 18 months - 14.2 MPG lifetime.

I drive 30 miles round trip every day I work and I go fishing on the beach sometimes

5.3 - 14.2

2017 ltz cc z71 18"wheels duratrac tires - 6.2 - 14.3 mpg (35k miles)

2020 trailboss custom with 100 miles on it 5.3 v8 - 10.5 mpg all city so far.....

My 2002 f350 5.7 liter (I think) regular cab with 39 gallon gas tank - 13.4 mpg (I used to track that with pen and paper religiously - had it when gas was $3--5 per gallon

1988 bronco custom with small v8 (not the 5.0) - 12.5 mpg if I can remember. On the beach you could watch the gas gauge drop it was funny..... I used to air that thing down to 12psi for the soft sand it wasnt a high torque engine.....Insert other media

Edited January 31, 2020 by jamesonjc

redwngr · January 31, 2020

2 hours ago, DogMom said:

Ingesting. I have the same truck and average 17.7 Highway going 60-65mph. Maybe 70 is the sweet spot like it is for my husbands 2500 duramax.

Sent from my SM-G965U using Tapatalk

Hubby needs to try 55, if mileage is a big issue.

DogMom · January 31, 2020

Hubby needs to try 55, if mileage is a big issue.

Not an issue. Just gets better gas mileage on cruise at 70mph than at 55 or 65 on a long trip.

Sent from my SM-G965U using Tapatalk

DogMom · January 31, 2020

Hubby needs to try 55, if mileage is a big issue.

We are fine with 11mpg @55mph with 2,500 lbs in the bed [emoji1]

Sent from my SM-G965U using Tapatalk

redwngr · January 31, 2020

13 hours ago, DogMom said:

Not an issue. Just gets better gas mileage on cruise at 70mph than at 55 or 65 on a long trip.

Sent from my SM-G965U using Tapatalk

Must be a magic dmax.

DogMom · January 31, 2020

Must be a magic dmax.

Who wouldn't want a magic duramax? [emoji1]

Must be his tuner settings.

giphy.gif?cid=349c9dd71d0a17c4e744d1cc01ca9af6fa275a5d13e6af49&rid=giphy.gif

Sent from my SM-G965U using Tapatalk

Gerstein1989 · February 17, 2020

I thought I was gonna get better mileage as well going from a 6 speed to the 8 speed but then I realized they also made the gas tanks smaller. It used to be a 98 litre tanks and now it’s a 90. But I get the same amount out of it than I did on the 6 speed.

elcamino · February 17, 2020

The biggest influence on fuel mileage is the connection between the steering wheel and the gas pedal. Driving at higher speeds increases aerodynamic drag (wind resistance), reducing fuel economy.

madconcept · February 18, 2020

I just did a hwy run in my truck.

Unloaded and relatively flat.

2019 Sierra Elevation 5.3, 8 speed, 4x4, Max Trailering package.

Level kit and 275/65R20, BFGOODRICH KO2 tires.

Thought I did ok averaging around 60-70 mph or 100-110kph. Trying my best to hyper mile, but didn’t quite work out 100%.

Canadian truck. I took a pic of both US and metric fuel economy and trip distance. Measurements can be changed in Dash display.

Edited February 18, 2020 by madconcept

TXGREEK · February 18, 2020

I just did a hwy run in my truck.
Unloaded and relatively flat.
2019 Sierra Elevation 5.3, 8 speed, 4x4, Max Trailering package.
Level kit and 275/65R20, BFGOODRICH KO2 tires.

Thought I did ok averaging around 60-70 mph or 100-110kph. Trying my best to hyper mile, but didn’t quite work out 100%.

Canadian truck. I took a pic of both US and metric fuel economy and trip distance. Measurements can be changed in Dash display.

If you’re this pickled over mileage, switch to highway tires, Michelin defenders. The tires on the trucks getting 24mpg at 65-70 aren’t equipped with AT tires.

You may also consider a tune, SuperChips

Sent from Above