2014+ Gas Mileage (MPG) Topic

[schultzy1957]

Here is GM's Response:

I just spoke with the Service Manager Kevin, at
Schweiters Chevrolet. He stated that your vehicle update should not have
affected your average MPG. Average fuel economy can be determined by a variety
of factors including cold weather, excessive idling, running electrical
accessories, terrain, road surface condition, etc. Your dealership has also
reached out to the GM Technical Assistance Team, and they have no information connecting
the reprogram to loss in average fuel economy. I apologize that I was unable to
find other possibilities for you, and understand how this situation has
frustrated you. If you wish to work with another dealership for a second
opinion on this issue, we'd be more than happy to locate one for you. If you
have any additional concerns, please let us know..

.

.

Just Perfect.....They talked to a " Service Mngr " at the dealership and he said...QUOTE.(.That your vehicle update should not have affected your average MPG.)

Why the heck is GM asking him??????

Why are they NOT asking there own people.....

TELL YOU WHY......... GM does NOT want everyone to know that the reason the recalls were done WAS " THEY DE-TUNED" the engine because the new motor is having LIFTER and VALVE and CAM problems......

It wont be long and .....THIS WILL BE ALL OVER THE NET....

By the way...

If you think GM gives a shit....THEY DO NOT!!!!!!

[schultzy1957]

reply

Look Back.......

The first 3000 miles the truck AVERAGED over 22mpg.

The next 3000 miles it has AVERAGED 15mpg.

YES.....That is a 7 mile per gallon DECREASE!!!!!

Do NOT try to blame this on me .

If it was NOT caused by the 2 updates that were done, THEN something has gone wrong somewhere else....WAY WRONG.....

This started before cold weather happened , this goes back to just after LABOR DAY.

No idleing , No Remote starts, ect.

Its Not bad driving habits. ( Do a computer scan. )

Also 90% of my mileage is HIGHWAY ..NOT CITY...

[timstech]

google search (gm calid) click on the TIS site enter your vin# in the box on the left provided marked get cal id click on K20 ECM,you can see what updates are listed and sometimes a brief description of what is affected

Edited December 12, 2013 by timstech

[dagwood2001]

well, I was told my truck was "heavy" by my dealership, and that was probably why I was averaging 14.2 MPG. Thanks, thanks for that.

[TJay74]

I seriously doubt it is the calibration or that GM detuned the calibration. It would be very easy to find that out, have someone with HPT scan the calibration and then we can compare it to another stock calibration and see if they are the same or not.

 

I don't see how you guys are getting such bad mileage, I have the 6.2 and am averaging over 15mpg and that is with the truck barely getting into V4 mode and with only 600 miles on the truck.

[pm26]

Guess I should have said, there is now 6000 miles on the truck...With that said , The last 3000 miles have averaged 14.7 N O T the 22.8 I was getting.

Something is definitely not right. My experience has been about 10 to 15% mileage variation depending on brand of fuel I use and ambient conditions. In your case dropping this far represents at least a 35% drop in mileage which is not normal. Either someone screwed up your valve timing , or ignition advance and rate of fuel delivery, or all of the above. Do you feel any loss of power or need to press the accelerator hard to make the truck respond? Have you tried different brands/octanes of gas to see if the mileage improves?

Edited December 12, 2013 by pm26

[schultzy1957]

Here is GM'S Responce..

Quote,

Our TAC department, which is a specialty team within General Motors
that provides additional technical assistance to dealerships. At this
time TAC has not found any correlation between the update that was
performed and a drop in average MPG. Since there are no service
announcements to reference relating to this issue, we have to rely on
the dealerships to perform a diagnosis and determine what is causing
your MPG to decrease.

 

Unfortunately, we're limited in the amount of assistance we can offer
if the dealership is unable to isolate the cause of your concerns. I
have your contact information on file, and will add our correspondence
to your case.

[wandern]

Out of curiosity, what is the BC/DIC computed mileage and what is your calculated mileage over a full tank?

 

How good of mileage can you coax out of the vehicle over a 25 mile trip on flat roads at a constant speed of 55mph?

[DanielAcosta]

For the record I have seen no change in mileage and I have had all the ECM/TCM/BCM updates completed. My gallery has DIC photos of mileage. Right now I'm at 12,500 miles and still consistently getting 20mpg with 34" tires. I usually go about 450-500 miles/tank. My best tanks have been 20-22mpg on highway trips at 75, though I have seen 24mpg at lower speeds (photos in my gallery). Hand calculations are generally within 0.5 mpg of the DIC display. The stock trucks I test drove were showing about 2mpg higher than my truck with oversize tires. And yes, I have a Hypertech so my figures are corrected for the tires.

[sapper1]

Ok, my second fuel tank is about done...lasted about 3 days. Right now I have a quarter tank of gas left and I have driven 224 miles. This is what I have noticed about my truck.

 

1. The truck definitely FEELS like it has no real power

2. I have to stay in the gas pedal to maintain speed.

3. If I let off of the gas and try to just "coast" my truck instantly starts slowing down as if I were slightly breaking even when im going down hill.

4. To get up to speed on the Highway I really have to get on to the gas and hold it there other wise I will go from 70 to 60 with in 3-5 sec.

 

This is the first actual pick up I have ever owned however, I have owned a Suburban since 2006 (recently traded for a 2010) but they both maintain their speeds a lot better.

 

Not sure what to think...

[Jon A]

Try checking your brake temperatures after driving for a while. You may have a stuck caliper or something causing your brakes to drag.

[allphaze]

my 2014 is getting 14.6 around town . isnt that the norm?

[mzodarg]

my 2014 is getting 14.6 around town . isnt that the norm?

Over the past two weeks, I've been driving around in Auto as it's been sh!tty weather were I live, mileage dropped to 14.5. Before that I would average between 16-17 mpg in town.

 

Mike

[JCthebigTree]

This last tank I'm showing an average of 9.4

 

Taking into account remote starts, about 300 pounds of weight in the bed, crappy weather w/o 4 wheel, and driving on a lot of hills, and only 800 miles on her...I'm still feeling like it should be better than single digits.

[svtkidd23]

Averaging 17 for lifetime.. Last 3 tanks have been 15.1