6.2L 8-Speed Gas Mileage

[lba0213]

What kinda mileage are you guys getting?

 

2014 guys, feel free to chime in as well.

 

Ive almost got 2k miles on mine and my mileage usually sits around 15.8, sometimes will jump above 16. I feel like under normal driving conditions here in NC, I should expect a little better gas mileage. 50% hwy and 50% city.

 

Also, I run 91 octane.

[nards444]

considering the 5.3 guys are getting right around 16ish, I wouldnt complain. With that engine I wouldnt expect anything higher for around town driving.

[BluByU14]

That is about what mine is.....but that is driving 80% secondary roads and 20% highway. With the extreme cold in the north east this winter, I have been allowing mine to warm up about 10 minutes or so before work each day, that cant help with the MPG's either. I am going on a 2500 mile round trip to Florida next month...hoping I can get into the 20's as I will be driving 99% highway.

[CounterMeasure]

I average 14.7mpg, which my commute is 50/50, where the highway is 75-80mph per posted speed limit, and its almost always with a crosswind. If I bebop along on a highway trip at 70mph without any real winds, I get about 19.5mpg.

[redwngr]

Onstar app says Lifetime - about 17.2 mpg (and about 2500 miles)

 

It was running about 19 lifetime til the recent cold spell.

[redwngr]

Onstar app says Lifetime - about 17.2 mpg (and about 2500 miles)

 

It was running about 19 lifetime til the recent cold spell.

[Chad2815]

Average 17, about 50/50, I have a 14 wi5h Max Tow and 3:73's. That's stayin at 75 on the interstate because 80mph hurts. 75 puts me at about 2 grand.

[hurricanoday]

I hope I get the advertised 14/20-21 when I get my 15 Sierra Denali 6.2......

[Ashtonman]

16.6-16.8 average with 70/30 city/ highway. 4500 miles. 21-22 on the highway driving under 75.

The cold spell has really hit mpg the last month.

I have found that not all 93 fuel is the same. For some reason I get the best mileage out of 93 fuel from Sams Club. Not sure who supplies them but I bet it is real 93 fuel. No cheating ( to big of a contract to loose). I am still collecting data on other brands but I have seen some so called 93 fuel (name brand) lose 2+ mpg. I think some gas stations are cheating.

[lba0213]

Perhaps I should give 93 a try and see where this puts me. Ive only been running 89

[Isriam]

first, you should run 93 always, the manual says you should (not must). i ran 87 and had better mpg than 93, but i had a lot less power. those are good gas numbers for the 6.2 don't let these 5.3 owners sway you. my 2014 i get 14 city and 20 highway.

 

second, you should look into a programmer with a custom tune if you want even better mpg.

 

third, remote start warm up will kill your mpg as well as idle, because its all calculated as a whole.

[redwngr]

Pretty sure the manual says 91, but your either way the L86 6.2 should be run on premium.

[nards444]

Pretty sure the manual says 91, but your either way the L86 6.2 should be run on premium.

problem is 91 is all we have around here.

[nards444]

Perhaps I should give 93 a try and see where this puts me. Ive only been running 89

One thing about this, is you may bump up MPG but it will cost more. So you would have to do a cost per mile to see what makes sense. For instance if you get 15.8mpg on regular, regular fuel is 2.41 here, 25 gallon tank cost $60 and that tank would get you 395 miles per tank for a cost of roughly 15 cents a mile. Now if you get premium and your MPG increases to 17mpg but cost you 70 bucks per tank, you get 425Miles per tank for a cost of 16.5 cents per mile, or costing you 10 bucks more per tank. Cost wise it doesnt really work.

[redwngr]

problem is 91 is all we have around here.

Curiosity got the best of me. Since the last post I checked, the manual does say 91:

 

If the vehicle has the 6.2L V8 engine

(VIN Code J), use premium

unleaded gasoline meeting ASTM

specification D4814 with a posted

octane rating of 91 or higher.

Regular unleaded gasoline rated at

87 octane or higher can be used,

but acceleration and fuel economy

will be reduced, and an audible

knocking noise may be heard. If this

occurs, use a gasoline rated at

91 octane or higher as soon as

possible. Otherwise, the engine

could be damaged. If heavy

knocking is heard when using

gasoline with a 91 octane rating or

higher, the engine needs service.