2014+ Gas Mileage (MPG) Topic

Grumpy Bear · February 25, 2020

On 2/9/2020 at 3:22 PM, David Roark said:

Best does not count. It is the average that counts. And if it is like mine, I have lost about 5-6 MPG the last 2 years with this direct injection engine. The more miles you put on, the carbon build up you will have and the worst milage you will get.

Not true. This is my 2015's trucks first 100,000 miles for each 10,000 miles driven. Hand calculated. Green bars were over winter months. Looks like she's still gaining to me. I've done no intake cleaning. I have no catch can. I run some injector cleaner via the fuel tank once each 5,000 miles. I burn any E-10. (Red Line SI-1 two bottles in one 26 gallon tank). I'm almost done with the next 10 thousand miles and it has dropped a bit as I've decided to increase my average speeds about 7 mph. Mid 26 mpg range.

People keep telling me the Sky is Falling. Maybe some day she will embarrass me but until she does...…..

emaxxer86 · February 25, 2020

I just finished installing the same airaid tube this weekend, at first it was alright.... then i went back and popped the airbox out and removed the air intake restrictor panel, it pops out so easily, now it really sounds impressive. my MPG probably dropped by 2 points, but it was fun and feels much quicker now. I'm also using the OEM airfilter.

What restrictor panel?

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flyingfool · February 25, 2020

its at the inlet side of the airbox. you need to pull the airbox to release it and remove

i should of installed my obd2 scanner and did a before and after on the CFM and MAP sensor just to see if i made any improved airflow, next time

Edited February 25, 2020 by flyingfool

johnnymordoc · February 27, 2020

Folks -

2014 GMC 1500 SLT

I have seen my mileage decrease - not sure if it is because I have switched tires from factory to Cooper SRX tires.

Is there any safe additive I can add to my gas to clean the fuel injectors instead of having to have them provide that service at the dealer?

I used to get between 18-20 mph on the last 50 mile tracker - now it is hovering 16.

Thanks in advance for any info.

JJ

Edited February 27, 2020 by johnnymordoc

Joe Wayside · February 28, 2020

I cannot believe the mileage some of you are getting. I have a 2017 crew cab, 5.3, 4x4 with max trailering package and 3:73 gears. I was struggling to get 14-15 mpg on stock size tires. I just put LT275/70/R18’s on my truck, and I’m getting closer to 12-13 mpg. I’m driving like a grandpa! This mileage included was before I installed my new tires. This is one thirsty truck.

Edited February 28, 2020 by Joe Wayside

David Roark · February 28, 2020

Yeah, that is what my MPG looks like. The more miles I put on the worse it gets. I blew $220.00 letting them put chemicals in manifold to get deposits off. Did not work. Waste of money. Looking for someone to blast it with walnut shells. Otherwise, I am trading it and going to a Ram port injection e-torque engine.

AdioSS · March 16, 2020

Just got home from taking the family on a trip to New Mexico for Spring Break. Got some impressive fuel economy during a flat low super stretch. 2018 Sierra Z71 6.2L crew cab 6.5’ bed with an eBay intake, muffler delete, & cheap bed cover as the only mods so far. I’ve been using the highest octane available at the pump which ranged from 93 locally to 90 out there.

TXGREEK · March 16, 2020

Yeah, that is what my MPG looks like. The more miles I put on the worse it gets. I blew $220.00 letting them put chemicals in manifold to get deposits off. Did not work. Waste of money. Looking for someone to blast it with walnut shells. Otherwise, I am trading it and going to a Ram port injection e-torque engine.

Down the road you’ll regret that purchase. As with just about every engine, that engine has its own forums featuring its negative attributes. I’d repair what you’ve got and keep it and this time add an additive every couple tank full it’ll help avoid future issues. I swear by Lucas Fuel treatment, helped with my 16 Yukon with rough idling, my 18 6.2 with 33k miles and still purring like a kitten.

Sent from Above

TXGREEK · March 16, 2020

Just got home from taking the family on a trip to New Mexico for Spring Break. Got some impressive fuel economy during a flat low super stretch. 2018 Sierra Z71 6.2L crew cab 6.5’ bed with an eBay intake, muffler delete, & cheap bed cover as the only mods so far. I’ve been using the highest octane available at the pump which ranged from 93 locally to 90 out there.

What was your average speed? My trip from Texas to New Mexico/ Arizona I’m at 80+ [emoji6]

Sent from Above

AdioSS · March 16, 2020

3 hours ago, TXGREEK said:

What was your average speed? My trip from Texas to New Mexico/ Arizona I’m at 80+

Sent from Above

This was during a slow stretch on the way home.

16LT4 · May 23, 2020

Took my ‘16 5.3 crewcab 4x4 from NY to FL a few weeks ago. It was in the 30s when we left and 80s when we arrived. My mileage increased directly with temperature, from mid 18s up to 23 mpg. Mileage increased roughly 1 mpg for every 10*F in air temperature; temps stayed in the 40s until SC as did my low fuel mileage, which helps take “winter fuel” off the list of explanations, leaving stoich and air resistance as the main reasons. With no one on the road, the truck was stuck on cruise control at 72 mph the entire trip; I went a full 450 miles without touching the brakes, slowing down only for off ramps. Best highway trip I’ve ever taken, and perfect conditions. This was on 87 octane. Back in January, headed North from FL to Norfolk, we hit a best tank average of 26.5 mpg, with the cruise set to 67 mph and 89 octane. That same trip saw almost 24 mpg on 89 doing 72 mph from the Treasure Coast to Key Largo and back. Down here in FL right now I averaged 18.5 mpg around town on 87, the current tank has 89 to see if the juice is worth the squeeze. The truck currently has 87.5k miles and has never had a valve or upper engine cleaning, other than some MMO in the oil a couple times.

Edited May 23, 2020 by 16LT4

DirtyAndy · June 2, 2020

My 2020 AT4 5.3L is really impressing me.

Computer average over 400 miles.

Calculated with Fuelly at every fillup.

Both were taken today when I filled up. Obviously the DIC is a little generous. But I was pretty stoked to hit 21.4 as it has been steadily rising with the warmer temps.

theamericandreamdave · June 18, 2020

2018 Z71 Crew Cab over 63100 miles the average FE is 19.9MPG.

theamericandreamdave · June 18, 2020

On 2/27/2020 at 8:22 AM, johnnymordoc said:

Folks -

2014 GMC 1500 SLT

I have seen my mileage decrease - not sure if it is because I have switched tires from factory to Cooper SRX tires.

Is there any safe additive I can add to my gas to clean the fuel injectors instead of having to have them provide that service at the dealer?

I used to get between 18-20 mph on the last 50 mile tracker - now it is hovering 16.

Thanks in advance for any info.

JJ

Yeah. Chevron Techron fuel system cleaner is the safest bet.

Grumpy Bear · June 18, 2020

6 hours ago, theamericandreamdave said:

Yeah. Chevron Techron fuel system cleaner is the safest bet.

Techron is one of a handful of injector cleaners using the PEA additive and it does work at a high enough dosing rate.

Red Line S1 is another as is Gumout Regane. Red Line has a white paper on their site worth a read. I believe it has some instruction on dosing for motors that have never had the injectors cleaned.