2014+ Gas Mileage (MPG) Topic

[Ton J]

Just picked up my truck, they did the rear window recall and held onto it for a few days when i told them the fire recall screwed up my mileage a few weeks back. They couldnt find anything wrong and said the truck is running normal. As a precaution they told me they completely reflashed the whole truck, re-did every flash (3 in total) since the truck was built (throttle body, transmission, and then fire recall flashes) and said they all went in perfectly (fire recall flash was weird they said because their internet went down in the middle of the flash?). But overall he said the truck is running "happy" now (whatever the hell that means). The technician said it will run weird for a bit though because it needs to relearn my driving habits and boy was he not kidding. The 30 mile highway trip home was funky, shifts were wacky and engine was all over the place for the first half and then evened out, I will note it was in V4 A LOT and the drone was really noticeable compared to before even with my stock exhaust. Hopefully when everything gets back to learning my grandpa habits it will be near the 16-18 mpg i was originally receiving. I will update you guys after a few tanks of gas.

Has you things gotten any better. Am doing between 14.5 and 15.1 called GM they got a Tech coming to my Dealer I told am going to report this.

[bladz1454]

Has you things gotten any better. Am doing between 14.5 and 15.1 called GM they got a Tech coming to my Dealer I told am going to report this.

 

Strangely enough, my HWY mpg has gone up significantly. I was getting like 16-18 before now have been averaging about 19-21 but my CITY mpg is still garbage (about 9-12) and since I do about 70% city and 30% highway, I am averaging like 13 mpg which i am not happy with. I will wait another tank or two before I talk to the dealer again.

[strike1st]

492 miles...70% city 11 mpg Lifetime

[fondupot]

On cold mornings my truck is getting around 15mpg to work. Tire pressure starts at around 32 psi. On the trip back with warmer temps and tire pressure back up to 35-36 I'm getting 18-18.5. Seems like the lower pressure and colder air hurts the mpg a good bit.

Also you have to keep in mind I'm running 275 60s without changing the speedo.

I'm running the 275/70-18 BFG which is a 10ply...60psi min, 80psi recommended...pressure doesn't seem to matter 60-80psi fuel mileage is same, with 5.3 it seems to HATE anything below @32F

 

I've been Averaging between 15-16 here the last several weeks. At times it's been well below zero. But for the most part in the 10s and teens.

 

When I first got the truck in September I was getting between 17-18 in same driving. I blame winter blend and the cold.

 

 

Sent from my iPhone.

[Kennedy81]

Its finally been above freezing here the past couple of days, around 40+ degrees and according the DIC, with the warmer temps, it appears I'm getting about 2-3mpg better than when it was below freezing out, around 20 degrees.
I have yet to run a full tank since it has warmed up, but based off the 25 mile average, I'm definitely up.

[fondupot]

Its finally been above freezing here the past couple of days, around 40+ degrees and according the DIC, with the warmer temps, it appears I'm getting about 2-3mpg better than when it was below freezing out, around 20 degrees.

I have yet to run a full tank since it has warmed up, but based off the 25 mile average, I'm definitely up.

 

I've noted the same.

[Dnt]

Update real world gas mileage 2014 Crew Cab SLT Z71 4x4 5.3 3.42 20in all terrain tires short bed with bed cover installed currently on second tank of nonethanol 87 octane. I haul approx 400 lbs of work tools with me in the bed at all times. Normal commute is about 24 miles one way 75% highway always stay below 70 and watch the lead foot but not holding up traffic. I park outside so a warm up typically of ten minutes is required to clear the windshield I usually just remote start and let it die then start when I get outside I start it with the key and drive off. Strange thing on the DIC meter is that after you really get into it and blow it out for a spell it seems to show much better mileage? Not sure why that is other than maybe it makes the variable valve setting different? Anyway here is what I had today almost ready for my next tank of nonethanol 87 octane. Continuing testing. Weather has warmed here in the last day or two and it does seem to be easier to achieve higher mileage results.

[Mckenzie]

filled it up and its almost on E with only 200 miles on the odometer... Should be getting around 8-9 which is down a whole lot from my average 11-ish... I dont know what the hell is up

[Bikewhisperer]

It below freezing half the year up here. I don't want 13mpg half the time. I'm pretty envious of some of the numbers I see here.

 

Sent from my SGH-I747M using Tapatalk

 

 

[2014Z71LTZ]

Seen a lot of talk on here about MPG going south after the recall update, i noticed the same thing but after thinking about this some more maybe its just more of the cold weather bad MPG. I got my recall done early January about the same time as the temps have really falling off in most of the country. I drive the same drive everyday one way to work 15 miles. In the summer months I was getting 20 MPG all the time, once the colder fall months came around I was is getting about 18 MPG, now since it has been colder than hell (beginning of January) I'm only getting 16 MPG. Also with the temp never going above 20 around here for the last month, on my 15 mile trip the water temp won't hit the 210' mark until I am almost to the end of the trip. I really think the crappy MPG is just due to the extreme cold.

Here's what I posted on Feb 1, I still believe it's the cold weather. Last 3 fill ups I've gone back to E85 and getting 14MPG+, compared to the 16MPG I was getting on gas. I think I'll stay on E85 until the weather breaks.

[Ulukslo]

Just drove from my house 65 miles to Tuscaloosa. We ate then cruised back through town to the mall. Left the mall, filled up with gas and drove home. 130 miles on OD and gas mileage was on 19.3 for whole trip. This is real world as it gets. Driving about 62-65 passed 4 cars also on two lane rd.

[Ulukslo]

[Mutau95]

Nice average with the 6.2 What is your driving style? I have gotten up to 24 MPG on a hwy trip but average 17-18 mpg combined with my 5.3 w/3.08 rear end.

[Ulukslo]

Driving style today was pretty easy. First car I passed was on a long straight so not alot of throttle to do so. Second car was kinda wild!! Alot of throttle!! When jumping on interstate for the mile of it that I ran I jump into traffic and run 80mph till I exit off the mile stretch. Around town pretty easy decelerating and looking ahead as much as possible. Thats where you save alot of gas!! DEFCO is what its called. But I usually drive pretty wild but wife n child was with me so.......... Im still wondering what a 5.3 with 3.73s would do on mpgs!! I know the truck we test drove home for a couple days was terrible on gas compared to a 3.42 truck because it had 3.08s . I would like to think your mpgs around town would come up tremendously with a little gear!!

[Jon A]

First highway trip with the Denali 6.2:

 

 

I have 34" tires and have not corrected the computer. Adjusting for the 7.4% error the actual numbers are 17.3 MPG at a 68 MPH average.

 

This was a round trip from the Seattle area to the top of Snoqualmie Pass (3000 ft elevation) and back again. The engine is still new (fewer than 300 total miles).

 

I'm pretty happy with that. It's rated at 20 for the highway, I've taken off the front airdam, lifted it 2" front, 1" rear, and put much bigger and heavier 34" tires on it.

 

 

On flatter ground it should easily be in the 18-19 range, mountain passes kill your mileage. So I think that's pretty good considering what this engine is capable of when you put your foot down.

Edited February 22, 2014 by Jon A