FUEL ECONOMY - Average miles per gallon seem very low?? Ways to improve??

[LisaandJoe Navarro]

Hi everyone, first time posting. I've noticed since I purchased my 2015 5.3l chevy suburban that the average miles per gallon is low. I dont rev my engine, I always keep the screen up to monitor my fuel economy as i drive. I seem to always avg 15-16mpg road and 17-18hwy....

 

Does this seem normal???

 

I put in regular unleaded from krogers and costco.

 

I have 43k miles on my vehicle 

 

Live in an area without high terrain.  Regular suburbia.

 

Something just does not seem right.  

 

Any input, help, modifications, changes required to improve?

 

- yours truly

A concerned chevy owner! 

Thank you!!!!

[cr250Silverado]

Per a Fuelly.com search the 5.3 suburban is reported to average 16mpg by real world users. So I would say your vehicle is in the norm.  

 

http://www.fuelly.com/car/chevrolet/suburban?engineconfig_id=125&bodytype_id=&submodel_id=

[DougFL]

Is your AFM working?  Are you running Full synthetic oil?  What rear gear are you running?  My 2016 Silverado 5.3L  with 8 speed and 3:42 gear averaged 20.7 mpg over 84,000 miles and typically got 22 mpg on the Highway.  My 2019 5.3L Silverado, with 8 speed and 3:23 gears is doing even better!  This is my current tank of fuel:

Edited November 4, 2018 by DougFL
added Silverado 5.3L

[LisaandJoe Navarro]

Hey Doug,

Thanks for responding.

 

How can I find out if my AFM is working?

How can I tell what speed and gear I am in?

[markitzero]

'16 Suburban with 44k and the lifetime fuel efficiency shown on the iPhone app is 16.3. I reset the trip computer every fill-up and I've seen the average for the tank as low as 12 and high as 19. 

[Black02Silverado]

Our 2016 Suburban gets that as well.  Our last trip up to D.C. we got 19mpg.  One trip we did got 21mpg.

 

[DougFL]

16 minutes ago, LisaandJoe Navarro said:

Hey Doug,

Thanks for responding.

 

How can I find out if my AFM is working?

How can I tell what speed and gear I am in?

The standard rear ratio on the 16 Suburban was a 3:42 unless you have a tow package.  On the Silverado the AFM would be indicated on the Dash when V8 changed to V4.

Edited November 4, 2018 by DougFL
spelling

[Donstar]

18 minutes ago, DougFL said:

Is your AFM working?  Are you running Full synthetic oil?  What rear gear are you running?  My 2016 Silverado 5.3L  with 8 speed and 3:42 gear averaged 20.7 mpg over 84,000 miles and typically got 22 mpg on the Highway.  My 2019 5.3L Silverado, with 8 speed and 3:23 gears is doing even better!  This is my current tank of fuel:

 

47 minutes ago, LisaandJoe Navarro said:

Hi everyone, first time posting. I've noticed since I purchased my 2015 5.3l chevy suburban that the average miles per gallon is low. I dont rev my engine, I always keep the screen up to monitor my fuel economy as i drive. I seem to always avg 15-16mpg road and 17-18hwy....

 

Does this seem normal???

 

Enjoy your Suburban and don't set your MPG expectations by what some members are achieving on their pickups!  I once owned a new  '86 Suburban and it didn't get close to your numbers!

[Black02Silverado]

You have to remember that the Suburban is one heavy beast unlike the Silverado's.  That and add people and cargo and the weight packs on. 

 

Might try running midgrade fuel for a few tanks and see what happens.  I run premium in ours.

[The Zip]

2 hours ago, LisaandJoe Navarro said:

Any input, help, modifications, changes required to improve?

There are other factors that can detract from fuel mileage, right off the top you can throw in speed, very large tires, type of tire (snow or highway, hard or soft), very low tire pressure, strong headwinds, dirty air filter, and clogged injectors.  Speed, tire pressure, air filter, and injectors can be done right away, those may gain you a mile or two.  I drive in uneven terrain and my Tahoe is consistently low twenties.

[Grumpy Bear]

9 hours ago, Black02Silverado said:

You have to remember that the Suburban is one heavy beast unlike the Silverado's.  That and add people and cargo and the weight packs on. 

The Suburban weight is about a thousand more than my RCSB. Hilly country, Ohio I see. The EPA highway number is based on speeds lower than most people drive. The Fuelly.com numbers are the averages of lots of vehicles over lots of miles. A fair representation I would think. 

 

 

[Rteefact]

Something must be wrong or not functioning. Could it be stuck in trailer-haul mode? I have a 2015 Tahoe and my low is 13 around town but consistently on the highway its 21-22. I've even hit 24.5 on long trips. Maybe it needs a reprogram at the dealer.  

[K2xxSteve]

Just got back from a 500 mile Thanksgiving road trip and averaged 19.1 mpg overall, including all local driving and at least 5 full throttle passes around idiots, including one double pass 40-75 mph on a two lane back road with a 55 mph limit and the idiot two cars in front not even hitting 40 mph. Without all that, I probably could have hit 20 mpg overall.  Easily hit 22 mpg on the highway, right on target, despite pushing through freezing cold and thick air. 1000 miles on the '18 Suburban, regular grade fuel, 3.42 gears, 22" wheels with factory Bridgestones set at 32 psi cold, 5 passengers and luggage plus a dog. I'm getting 12-14 mpg in 100% local city traffic, which is about what I expected to get. The biggest issue there are the short trips and the oil never really getting up to temperature (oil temp lags coolant temp by about 10 minutes - is there a way to hack the DIC to show oil temp rather than coolant temp? Probably not). My work commute is a whopping 1 mile so yes, mileage is terrible, but at least I don't have to go very far. Lol

Edited November 25, 2018 by S P
added pic