Jump to content

Recommended Posts

 I admit it; I'm a heavy footed driver. I'm not in a hurry to get anywhere, I just like gowing fast. I have a 2015 C7 Stingray also with the 6.2L engine. 

 So, I drove my brand new 2019 GMC Dark Sky Metallic AT4 from Chehalis, WA to Bridgeport, CT for the project I'm currently working on. The best gas mileage I could get was 15.6mpg! There's gotta be something wrong. When I drove it off the lot my buddy who was following said he'd seen an excessive amount of smoke coming out of the dual exhaust. I drove it the 75 miles to the house and it did not appear to happen again. Nor have I noticed any smoke since.

 I'm going to take it to the dealership here in CT and have them look at it "For the record", and I'd like any input you all may have. 

 The 2018 Chevy Silverado LTZ I sold to buy this truck had the same 6.2L with an 8 spd tranny (AT4 has 10spd), and I drive this the same as I did that truck, but the LTZ got a steady 19.5mpg if not 21-22. What gives? My AT4 has dual exhaust,  a cold air intake, 20" tires with dual purpose tires (This may cause a drop).

LTZ-AT4.jpg

Link to comment
Share on other sites

  • BigEdB changed the title to AT4 6.2L Poor Gas Mileage

The first 100 or so miles in my trail boss the mileage sucked. After the first fill up and reset of the mileage calculator it got significantly better. Are you calculating the economy yourself or just going off the display?

Link to comment
Share on other sites

It’s a lifted truck with a 6.2 liter. It’s not going to be great. You can wipe  two miles per gallon off for the lift alone.

 

My 6.2 AT4 with the Duratracs gets 13.5 around town and 18 mpg at most on the highway.

 

A friends ‘19 6.2 Denali is getting roughly 2 mpg above both of the numbers I’ve seen.

 

The lift kills the aerodynamics.

Link to comment
Share on other sites

Are any of you using Auto Stop/Start to measure the mileage? Have you compared both with and without Auto S/S on same road, length and weather conditions? Highway or off-road prolly not gonna matter much but city with some combo driving is what I do most. 

Link to comment
Share on other sites

14 hours ago, BigEdB said:

 I admit it; I'm a heavy footed driver. I'm not in a hurry to get anywhere, I just like gowing fast. I have a 2015 C7 Stingray also with the 6.2L engine. 

 So, I drove my brand new 2019 GMC Dark Sky Metallic AT4 from Chehalis, WA to Bridgeport, CT for the project I'm currently working on. The best gas mileage I could get was 15.6mpg!

You drove 3,000 miles on the freeway in one trip? that should be a pretty good indicator of your mileage. I only have one question for you- What speed do you drive? By your posted mpg and the fact that you have a corvette (and admitted to like going fast), I'm guessing you average double digits over the limit. That might be your problem. Try driving with the rest of traffic and watch your MPGs go up. It doesn't matter how much you floor it from a stop, once you reach cruising speed you are just pushing air out of the way. Air resistance is much higher at 85 than at 70 mph.

Link to comment
Share on other sites

Are any of you using Auto Stop/Start to measure the mileage? Have you compared both with and without Auto S/S on same road, length and weather conditions? Highway or off-road prolly not gonna matter much but city with some combo driving is what I do most. 
Mine is with auto start on. I will try with it off and get back to you.

Sent from my SM-G965U using Tapatalk

Link to comment
Share on other sites

  • 5 months later...

I have the same exact issue. I had a 2018 all terrain 6.2 with 8 speed and consistency got 19.5 to 20 average sometimes hitting 21 average mpg driving 70 to work. Traded in for a 2019 AT4 6.2 with 10 speed and now have consistent 16.0mpg driving the same route with no changes. I'm about to hit 5k on the miles. Very dissatisfied with the new mileage and wish I had my 2018 back. If you find out anything to increase the mileage or why it has gotten worse, please let me know. Love the new truck but what gives? 

Link to comment
Share on other sites

  • 3 months later...

Hey everyone, I know this is a 6.2 thread,  but I've got a '19 5.3 Elevation 8 speed and I've also noticed worse gas mileage than my 2018 5.3 6 speed. About 1.5-2mpg worse. When I bought my 2019 it actually came off the lot with really low tire pressure, only about 30psi on 50psi capable tires, I put them up to 40 ish and it did help a bit with my mileage. Not a big difference but a half mpg or so. Worth checking your tire pressure and trying going up a bit higher. I was surprised how low the tire pressure from the factory was and not sure if that's standard or a one off

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.

Guest
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.