Jump to content
  • Sign up for FREE! Become a GM-Trucks.com Member Today!

    In 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. From buying research to owner support, join 1.5 MILLION GM Truck Enthusiasts every month who use GM-Trucks.com as a daily part of their ownership experience. 

Your best 25/50/400 mpg

Recommended Posts

Gas engine....  18.2mpg, 17.7mpg, 15.2mpg for 400 mi.


The 18.2 and 17.7 were set at the same trip, descending from the highest point in Ohio.  Couldn't believe when I saw that number on this truck.


The 15.2 was not set on a highway road trip, it was putting back and forth to work on rural roads.    Not surprisingly, the 80mph interstate driving trips don't give as good of mileage as my 50-55mph commute.



Link to comment
Share on other sites

Folks - I was seeing my mileage at 18 - 20 mpg - up until I had to replace my battery?

Not sure if it is a coincidence - not I seem to be averaging about 13.2 and best is about 16.

I have about 70K..

2014 GMC Sierra SLT.

Any thoughts?

Clean the fuel injectors?

Add an aditive to tank to clean the fuel system?


Thanks in advance.


Link to comment
Share on other sites

8 hours ago, ewbldavis said:

14, 14, and probably 14 ?


My "best" was at 17 when I bought truck...it's since changed to like 14.


Maybe it's issue with truck, or my driving style, or whatever - but she's a thirsty bitch. I love her anyway. :)

sumbitch can handle anything though!

Link to comment
Share on other sites

On 12/17/2019 at 9:58 AM, SILVER SLED said:





On 12/17/2019 at 9:44 PM, Ryno12 said:

These can’t be HD numbers?!


Sure they can....

When a Cdn truck is set to inch units instead of metric, it displays mpg for 31/62/404 instead of 25/50/400


My L5P currently is at

31  - 34.1

62 - 29.8

404 - 24.4


It has lots and lots of full tank averages over 20 mpg which means 600 miles between fillups.  On flat 2 lane with no wind I get the 'last 31' over 25 regularly.

Yes, it does lots of steady state driving with cruise on.

No, it doesn't tow much. 


DEF is a little over 1100 mpg.


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.