first small road trip. terrible MPG

[ct_corey]

Saturday I drove from mid CT to Portland Maine( 200 miles). On the way I set the cruise control around 78. I only was getting around 16.7 mpg. I used 3/4 of a tank getting up there. On the way back I set the cruise lower to around 75ish. I couldn't get more then 17mpg out of the truck. Truck is a 16 custom, 5.3 6 speed with the tow package. I kept an eye on the 4cyl and 8cyl switchover and the truck was constantly going back and forth. It would never stay in 4 cyl mode for more then a few seconds. The tuck has a kn air filter and besides that its stock. When I first bought the truck I was getting around 17 around town. I do have a 1.5 level kit in the front but I can see that killing my fuel economy that much. Anyone have the same issue?

[2014KL]

It's the winter blend gas and cold weather. Mine is the same way on a hot summer day I can set the cruise to 70 and get 24 mpg in the winter when it's below freezing mine struggles to hit 18

[Ezekiel2517]

I have noticed much worse mpg lately even in south texas. It has been in the 40s on a fuel road trips, and we usually have a strong crosswind to fight with. In the summer I was getting about 20. Now its consistently 17-18.

[Grjfer]

Try turning off grade braking.

[njk4o5]

my 14 high country 4x4 with 90k miles only gets about 16-17mpg. all stock with tonneau cover

[cbrsilv15]

Setting the cruise to almost 80 mph.... No wonder your MPG is terrible!

 

 

 

According to the U.S. Department of Energy (DOE), most cars’ fuel efficiency peaks at speeds from 35 to 60 miles per hour. After 60, though, fuel efficiency does drop significantly; the DOE says that every 5 miles per hour you drive above 60 is like paying an additional 24 cents per gallon for gas. That’s because at higher speeds your car encounters more wind resistance and the tires encounter more rolling resistance.

[Donstar]

Nothing terrible about your gas mileage. That is what I get when I set my cruise control for over 75 mph. I have to cruise at a lower speed if I want to see significant improvement. If you cruise at a lower speed you will also probably see a lot more of the V4 mode.

[Sierra706]

I travel that route from CT to NH frequently. Cruise control will get much worse mileage due to the hills. It's much more efficient to keep the throttle at the same position and let the truck slow down uphill and speed up downhill than it is to hold a speed uphill and not take advantage of gravity on the way down.

 

 

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[Sierra 5.3]

I set my cruise at 73-74. This is where I typically get my best mileage. Both my father and I have tested this, and we both got better gas mileage at this range than we did running 65mph. Don't ask me why, but it's true. I have a 15 Sierra DC. He has a 15 Sierra CCSB.

[Krusty]

^{There's more to life than MPG - I would buy the 6.2L I have on order without the V-4 if I could.}

 

^{That said - be sure and hand calc your MPG, don't trust the read-out. Try a 60-65 mpg trip on flat roads - sweet spot for MPG..........}

 

[Heavy 5.7]

Nothing is "killing" the "fuel economy", that's just the way it is.

[f8l vnm]

yeah agreed with the above. once you go above 65 , mileage drops significantly

[Andy Seibel]

I set my cruise at 73-74. This is where I typically get my best mileage. Both my father and I have tested this, and we both got better gas mileage at this range than we did running 65mph. Don't ask me why, but it's true. I have a 15 Sierra DC. He has a 15 Sierra CCSB.

 

Not sure I believe that scientific testing.

 

The best mileage I ever got on a tank was about 25 mpg, up north in September on a 55 mph speed limit 2 lane highway with no stops. I set the cruise at 60 and just steered between the lines.

 

Driving 70+ will give significantly worst MPG. So the OP's 17 mpg is not surprising at all, and the level kit will affect it compared to stock.

I'm not in that big of a hurry, so i set the cruise at 70 exactly on the interstate and get around 18-20 mpg per tank. And yes, the DIC reading is a little high, but usually within .5 mpg of the hand calc.

[Sierra 5.3]

 

Not sure I believe that scientific testing.

 

The best mileage I ever got on a tank was about 25 mpg, up north in September on a 55 mph speed limit 2 lane highway with no stops. I set the cruise at 60 and just steered between the lines.

 

Driving 70+ will give significantly worst MPG. So the OP's 17 mpg is not surprising at all, and the level kit will affect it compared to stock.

I'm not in that big of a hurry, so i set the cruise at 70 exactly on the interstate and get around 18-20 mpg per tank. And yes, the DIC reading is a little high, but usually within .5 mpg of the hand calc.

It's .5 high on mine. And I understand you disagreeing but I've proven it to myself and my family so that's good enough for me.

 

 

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[Fishtail8]

I find with mine I can get better mileage and have it stay in 4cyl more when I don't use the cruise control. It feels like the cruise is always using to much pedal to maintain the speed. Not that a guy is going to pick up 5mpg that way, but I've noticed a little improvement. Bottom line, it's still a brick shaped truck.

 

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