Gas MPG- idle gas burn

[Ricc]

On 11/16/2021 at 3:04 AM, Transient said:

Should've bought a 4 cylinder.  Fewer cylinders mean less gas burned. 

Hmmm, the 2021  2.7 turbo sucks fuel at extended idling also, It lowers your average gas mileage. 
By not idling (30 minutes daily lunch breaks)

my average runs about 18.9 mpg s per tank compared to 16 mpg idling. 
I finally figured out that the auto-stop feature isn’t that bad, if you use it correctly. 
What I’ve found was to not go from brake to gas pedal immediately when the light turns green, I ease off the brake enough that it restarts fully before hitting the gas pedal. 
My 2018 5.3 didn’t care how I drove it. 
It’s all about driving habits. 
 

 

 

[SteveO_AT4]

Not sure how many people know this but if you have a Sam's club membership you can save around 50 cents per gallon on 91 octane. Filled up yesterday for $3.30. 7-Eleven across the street was $4.02. Now it's not considered top tier gas incase that's a worry for anyone. 

[Transient]

1 hour ago, SteveO_AT4 said:

Not sure how many people know this but if you have a Sam's club membership you can save around 50 cents per gallon on 91 octane. Filled up yesterday for $3.30. 7-Eleven across the street was $4.02. Now it's not considered top tier gas incase that's a worry for anyone. 

Thanks for mentioning the Top Teir part.  That is a concern for me.  Sounds like you're in California or higher altitude if you're using 91 octane.  I'm a Sam's Club member, but the closest one is 20 minutes away.  That's a heck of a trip to save $10 in gas with each fill up. 

[swathdiver]

On 11/14/2021 at 8:30 AM, steve cury said:

Hey All

newbie, Sierra elevation 5.3/8 8 speed. just bought and in construction using truck alot and notice major gas burn in idle. compared to old Ford F 150 or Ram it seems there is not a restrictor. like the hwy mpg/ but city really sucks. 

Any thoughts or chips to use to save gas burn at idle ?

My old '96 F150 with a 302 would get started up at 6 am and run until about 6 pm during the week and got 12 mpg.  That was a 200 horse motor.  My old '09 Yukon burns about a gallon an hour idling, if it idles all day I've seen 7-8 mpg with some towing.  This motor makes over 300 horses.  Yours makes almost 400 horses.  

 

You could get the inline 6 diesel or that turbo 2.7 4 cylinder that puts out more torque than my 5.3, not going to burn as much at idle.  Anyhow, it's the cost of doing business, you write it off (fuel) and depreciate the truck.

[KARNUT]

4 hours ago, SteveO_AT4 said:

Not sure how many people know this but if you have a Sam's club membership you can save around 50 cents per gallon on 91 octane. Filled up yesterday for $3.30. 7-Eleven across the street was $4.02. Now it's not considered top tier gas incase that's a worry for anyone. 

Generally after church on Sundays we fill the wife’s car at Sams with regular gas. I drive it once a week to make sure it’s good to go. It’s a five cent discount. I never noticed any difference for other grades, I’ll check it out.

[redwngr]

On 11/15/2021 at 6:19 PM, Grumpy Bear said:

 

Steve...Once upon a time a long time ago in a land far far way was a motor with a carburetor and Kettering ignition and in those days the tune from the factory was plain awful. Almost anyone could improve combustion, economy and power with a screwdriver and a matchbook cover. 

 

Those days are past. Todays tune are much leaner and cleaner and while a few real sharp guys with some expensive equipment can get a few more horsepower from a stock motor even they can not do so as cheaply as we once could. 

 

If you want to make a real difference in your mileage buy yourself some 'feed back' like a Linear Logic Scan Gauge II plug in and teach yourself to drive frugally. Let it instruct you on your habits in real time. There is some to found as well in proper maintenance and good lubrication choices but there are no longer major slices of pie to be taken from the tin no matter what the marketing types are saying. 

And now we have the fuel mileage graphic that can do that. 

 

Instantaneous and most recent 25 mile averages screen can be used for that. 

(when the 'metric' dash has miles selected for units it gives a 31 mile screen on these trucks)

 

[KARNUT]

I have fun with the mileage being shown in vehicles. I get to tease the wife that I get better fuel mileage than her. I may drive harder at times but I anticipate red lights and my idle times are less. 

[customboss]

TOTAL COST OF OWNERSHIP is key, not one aspect of the cost of a truck or transportation. 

[BlaineBug]

The fuel saving "chip" is DFM, dynamic fuel management.  You can't get any better than running on as little as 2 cylinders (4 cylinders minimum for AFM, active fuel management.)

[steve cury]

5 hours ago, BlaineBug said:

The fuel saving "chip" is DFM, dynamic fuel management.  You can't get any better than running on as little as 2 cylinders (4 cylinders minimum for AFM, active fuel management.)

My new Sierra 2021 is sold without DFM chip and is only 8 speed trans. I lifted my truck 3 inches and bumped up tire size to an All terrain. Looking into a add in computer chip and or a cold air intake and exhaust. I was getting 22 to 24 mpg on highway. city was like 15 to 16. I lost 4 to 5 mpg with the lift and tires. it sucks but love the lift.

[steve cury]

15 hours ago, SteveO_AT4 said:

Not sure how many people know this but if you have a Sam's club membership you can save around 50 cents per gallon on 91 octane. Filled up yesterday for $3.30. 7-Eleven across the street was $4.02. Now it's not considered top tier gas incase that's a worry for anyone. 

 

[steve cury]

hi SteveO.  Other question i seem to get longer burn on qas when I use 91 or 93 Octane. gas last longer but MPG may be close. the gmc manual calls for 93 octane and I go to Costco and its almost same price as Shell low grade 89..Maybe its all BS but I am doing Mods and looking to make my truck the best.  Wanted a diesel sierra but couldn't find it. I want to squeeze out a few MPG if I can which equates to 24 gallons x 4 mpg or almost a 100 miles per fill up.  kind of wish GMC did a larger tank like Ram or Ford. 

[BlaineBug]

1 hour ago, steve cury said:

My new Sierra 2021 is sold without DFM chip and is only 8 speed trans. I lifted my truck 3 inches and bumped up tire size to an All terrain. Looking into a add in computer chip and or a cold air intake and exhaust. I was getting 22 to 24 mpg on highway. city was like 15 to 16. I lost 4 to 5 mpg with the lift and tires. it sucks but love the lift.

Did you ever program for the larger tire size?  I'm assuming the entire outer diameter of your new tire and wheel combination is larger than the stock tires right?  If you didn't program your speedometer will be showing a slower speed than actual and as a result your mileage traveled will be lower than it actually is as well, leading to believe that your fuel mileage has suffered more than it really has.

[steve cury]

Blaine, not yet. looking at Chip plug in Programmer. Any recommendations ? would be good to find one that can do that tire size mod and save a few mpgs. Seems lower gears near more power to move heavier tires and new step bars. I have read about that dead lower weight vs. weight above shocks. 

[BlaineBug]

2 hours ago, steve cury said:

Blaine, not yet. looking at Chip plug in Programmer. Any recommendations ? would be good to find one that can do that tire size mod and save a few mpgs. Seems lower gears near more power to move heavier tires and new step bars. I have read about that dead lower weight vs. weight above shocks. 

Lower gears are best when you increase tire size for sure.  There is also some truth to unsprung weight.  I don't have any recommendations on where to get a tune either.