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2014+ Gas Mileage (MPG) Topic


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I'm curious about something, maybe you guys can answer:

 

Remember the post from a GM Tech telling us how GM screwed up the 900s E85 calibration and constantly switching gas types would forever kill your MPG because the computer would get stuck on a certain E% no matter the gas.....

 

Did they fix that? I'm sure its too early to tell but has anyone heard anything?

Maybe someone remembers the name of that old thread...

Edited by SnakeEyes 325is
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So far I've gotten 16.8 average and best of 22 MPG, all DIC calculated. So far, all has been city driving. I manually calculated the first tank and it was .3 different. IMO, no need to continue a manual calculation.

 

Truck has 4100 miles on ODO, I purchased it with 3500 miles (Owners Demo) I'm pleased with the mileage.

 

Mike

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My lifetime average right now is 18.8 mpg. I average about 14 mpg in the city since my commute is 2.5 miles with 5 stop lights in between, two of which are on about a 2 min cycle. My best tank is 24.2 mpg at 69 mph using the a/c. My best 25 mile average is 28.3 mpg, with my best 50 mile being 26.6 mpg. I calculate all of my tanks manually since my DIC is all over the place. It has been right on a couple of times and has been as much as 2.3 mpg off! It usually sits between 0.5 - 1 mpg off. My truck has the 3.42 gears and 20" wheels, all stock.

Edited by thehad
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I just got my truck last weekend and was very impressed with my in-town MPG - averaging aroung 17.5. However, my highway MPG is very disappointing. Driving flat coastal plains here in south texas, I only got around 18 doing 70 mpg. That seems ridiculously low. I notice that it virtually never shifts to V4 at that speed either. My best hwy MPG is when I am around 55-60 MPH, then I can almost get the EPA 22mpg. For the folks getting 20+ at 75MPH, I don't know how that is possible.

 

When I bought the truck I traded in my old truck and a motorcycle that I trailered. I left the lot with the empty trailer on this new truck and drove it about 20 miles. I wonder if the computer "learned" incorrectly on those first few miles. I switched over to Manual to check things out toward the end of my ride and noticed that is was going as low as 4th gear while going down the highway.

 

3.43, 5.3, Crew Cab, 4wd,

Edited by Zuhl555
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I just got my truck last weekend and was very impressed with my in-town MPG - averaging aroung 17.5. However, my highway MPG is very disappointing. Driving flat coastal plains here in south texas, I only got around 18 doing 70 mpg. That seems ridiculously low. I notice that it virtually never shifts to V4 at that speed either. My best hwy MPG is when I am around 55-60 MPH, then I can almost get the EPA 22mpg. For the folks getting 20+ at 75MPH, I don't know how that is possible.

 

When I bought the truck I traded in my old truck and a motorcycle that I trailered. I left the lot with the empty trailer on this new truck and drove it about 20 miles. I wonder if the computer "learned" incorrectly on those first few miles. I switched over to Manual to check things out toward the end of my ride and noticed that is was going as low as 4th gear while going down the highway.

 

3.43, 5.3, Crew Cab, 4wd,

I thought the exact same thing when I got mine, I was like city mileage is doing ok, then went on a highway trip and it was pretty much the exact same as city.

 

The way back on that trip i got alot better mileage, and actually my city mileage is better now too. I think maybe these engines just need to get past their break-in period, however long that be.

 

I actually have the 5.3 and the 3.08 and was thinking about swapping for a 3.42 while the truck was still fairly new so I would be more happy with it. But now it's getting EPA numbers and better consistently.

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Now that I'm at 1k miles, I'm doing about 19.5 80% highway/20% city. Not bad. For me, coming from a smaller truck, to get the same mileage out of a bigger truck with a significantly bigger engine, I'm impressed.

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DIC is very accurate on mine as long as I use the same pump every time. Different pumps turn off soon or later so if your getting gas at different stations or even a different pump ever time the DIC isn't going to be accurate. After you use the same pump and use the auto shut off multiple times you will see better accuracy, then you can start trusting your DIC.

 

My gas milage always starts off low and then climbs as I get more miles on. Every time I will start off around 17.5 and think I'm never going to average 20 but by the time I need gas I'm close to 20.

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I'm currently driving a 2005 GMC Sierra 2500 HD 4wd 6.0. and I average 12 mph. 11 city, 14 hwy. I CAN'T WAIT until I pull the trigger on a 2014 Sierra SLT crew cab 4wd and can avg @ 18 mph. I avg 14,000 miles a year. That would mean 389 gallons less a year, at $3.15 avg price, thats $1,225 a year or $102 a month savings. Ahh.... thats going to make that montly loan easier to swallow.

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DIC is very accurate on mine as long as I use the same pump every time. Different pumps turn off soon or later so if your getting gas at different stations or even a different pump ever time the DIC isn't going to be accurate. After you use the same pump and use the auto shut off multiple times you will see better accuracy, then you can start trusting your DIC.

 

My gas milage always starts off low and then climbs as I get more miles on. Every time I will start off around 17.5 and think I'm never going to average 20 but by the time I need gas I'm close to 20.

 

But what about the variation in the flow from the pump depending upon how full or empty the station's tanks are? Wouldn't that make a difference in when the pump shut off?

 

I think you are reading too much into this!!

 

Mike

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I just drive from Pittsburgh to St Louis (623 miles each way). Here's what my DIC says...

 

Best 25 miles - 22.8

Best 50 miles - 20.9

Best 400 miles - 19.8

 

Overall when I calculated by hand I got 20.09.

 

I had my cruise set on 75 probably 95% of the time. All highway driving. Regular gas (87 octane from Costco). Also, I have the SLT with 3.42 gears and 22's.

 

I'm going to try premium gas on the way back and see how much of a difference (if any) that it makes.

 

Sent from my SCH-I535 using Tapatalk now Free

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My mileage after two fill-ups (739 miles) is 20.07 mpg. This is not a DIC figure, but, an actual calculation based on 739 miles / 36.81 gallons.

 

I drive 10 miles each way to work 4 days a week via country roads. This also includes 400 miles of highway driving between 60 and 70 mph.

 

Not bad for a V8 that's a long way from being broken-in.

 

I use an Android application on my smartphone to track my mileage. The app is free and is call "FillUp".

Edited by DaveInPickerington
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After 2 hours of mixed driving up to the cottage including sitting in traffic and a long highway jog I averaged 25.6 MPG. This truck isn't far off from what I got in My cobalt ss so I'm not regretting the purchase what so ever as far as gas worries go. When sitting on flat even highway and cruising at 110 km/h, it would almost constantly stay at 30 mpg and would always stay in V4 mode.

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  • 2 weeks later...

Im averaging 10-11 in town on E85, but then again I remote start every morning, hit about 7 or 8 lights on my 2.5 mile commute, and no telling how many times per day the valet guys move my truck while i'm at work. 22 on the highway running 80mph on regular gas. Stock 5.3 w/ 3.42s

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I don't know how you guys are getting these mileage numbers. The DIC shows a 50-mile best of 28 (not sure how true that is) but my 'city' numbers are around 11s and highway closer to 20 (s. Cal to Vegas) @ 70 mph. I do live in a 'hilly' area. I have a 7-8% grade for 3/4 of a mile just to leave my neighborhood. But even with the hills, I am driving some other flat too, in city. I'm accelerating smoothly and am trying to get better mileage numbers, so I am not lead-footing (not babying it either as I want to train the tranny by my normal driving patterns). Am I doomed here? Is anyone else experiencing these kinds of numbers? Is a 'California' Sierra different than the other states models? 5.3 with 3.08 axle.

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