2014+ Gas Mileage (MPG) Topic

[Ton J]

They had me take it to another Dealer to check it out. They reprogramed it again they said there is a problem with the Active Fuel Management System the manager has one and he said his MPG has went down as well and customer are starting to come in and complaining. But I looked my truck up by VIN there was program issue before it left factory. This will make the 3rd time for reprogram now be understand if they have any problems when reprograming it can damage the ECM.

Service Manager told the AFM system is using more gas instead of less gas. So it comes down to the sensors now.

[strike1st]

 

 

 

 

[strike1st]

The 19 mpg's was a 40 degree day on the highway 70 mph with a 30mph sustained gusting to 50mph tail wind.

Edited March 18, 2014 by strike1st

[iCryWheniGoPoop]

My dlc shows a max of 35.1 mpg on the 25 mile average which is useless if you ask me. I do get considerably better MPG than what is reported here though. I hope you guys get it lined out and get the same.

[Ton J]

My dlc shows a max of 35.1 mpg on the 25 mile average which is useless if you ask me. I do get considerably better MPG than what is reported here though. I hope you guys get it lined out and get the same.

Its starting to become a big issue now that people are seeing for themselves now as well.

[gone_fishing]

This is the best I've seen so far. I had the cruise set at 55mph with a good 20mph tail wind. This is not typical for me. I've been averaging 16-17mpg throughout this cold winter. Now that it has warmed up I've been seeing 20mpg on interstate. Hopefully see 22mpg when we are off winter fuel and back to normal temps.

[2014GMC]

Had 1.5 hours of highway drive time home today. Averaged 20 MPG for the last 50 miles. Or at least that's what the truck was showing.

Crew Cab 4x4 with the 6.2

70-75 mph, 55 degrees, pretty much flat interstate roads on I-10.

I'm pretty impressed!

 

 

 

Sent from my iPhone using Tapatalk

[Hootbro]

Next time you do a fill-up, you may want to do a manual calculation and not trust the DIC reading. Many to include myself, have noticed the DIC MPG reporting to overstate by about 1 MPG higher than what it actually manually calculates out to.

[WesternPa.gmc]

Thats way better than i have averaged, but then again i'm driving up hills all day. haha I average about 16.5

[mzodarg]

Just did a 230 mile day trip to OKC and back-10-15 mph head wind going up, 5mph tail coming home. Diablo 91 octane tune, had about 120 miles on the tune so fuel trims had learning time.

 

I average 19.5 MPG running 75-80 MPH DOD is disabled Best was 22.5. Diablo tune is better than stock, TCM could use more work along with torque management. Data logging this afternoon, so I can get the files off to Lew.

[iCryWheniGoPoop]

Next time you do a fill-up, you may want to do a manual calculation and not trust the DIC reading. Many to include myself, have noticed the DIC MPG reporting to overstate by about 1 MPG higher than what it actually manually calculates out to.

 

This is true, mine can read as much as 1mpg off but it can read high or low.

[strike1st]

Next time you do a fill-up, you may want to do a manual calculation and not trust the DIC reading. Many to include myself, have noticed the DIC MPG reporting to overstate by about 1 MPG higher than what it actually manually calculates out to.

 

I'm doing a hand calc on this tank and from here on out...but if the DIC is showing 1 mpg better than I'm actually getting...holy wah...I'm screwed.

[Dnt]

Made a little trip up to KY yesterday about 500 miles overall. Running the E85 fuel now for a couple of tanks. It appears that it is not going to be as bad as I thought on the highway mileage. 2014 GMC Sierra CC SB SLT Z71 4x4 5.3 3.42 20" wheels. I will continue to buy the E85 I really like the feel of the increased HP and Torque it really messed up my first tank of E85 mpg my normally conservative driving was transformed into jack rabbit starts and tire barking. Now back to normal and mileage is just about right where the 10% ethanol 87 octane was at. Note I am tracking on the Fuelly site and it looks like the DIC is pretty accurate over the longer mileage ranges. I do not think the 25 and 50 ranges are far enough to be a true average but they are very good training guides for how to drive to get good overall fuel mileage if you pay attention.

Edited March 20, 2014 by MyFavTruck

[Ton J]

I'm doing a hand calc on this tank and from here on out...but if the DIC is showing 1 mpg better than I'm actually getting...holy wah...I'm screwed.

You starting to see what am saying now. And I have been dealing with since the first update before fire recall

[MD2014]

Next time you do a fill-up, you may want to do a manual calculation and not trust the DIC reading. Many to include myself, have noticed the DIC MPG reporting to overstate by about 1 MPG higher than what it actually manually calculates out to.

I have been tracking my mileage since day one. My first two tanks were very close by hand. The next 5 or so fill ups have all been off by approx 1 mpg. The computer adds an extra mpg somewhere everytime.

 

Highway or city does not seem to matter as well.

 

Stock 6.2L 3.55 gears 4x4