Fuel Economy Using Cruise vs. Human

[Mickey_D]

I used to be able to get better mileage in my 2005 1500 Sierra without cruise - if I tried hard it would get 19 on the highway driving it easy. With the new 14 I get about 17 with me driving it easy, but with the cruise I managed to get 21.4 (according to the DIC) on a 50 mile highway run between 65 and 80 (I-35 with moderate traffic). The DIC reported 17.8 on the tank and actual was 17.5, so it is reporting pretty fairly close. Seems like the throttle by wire system does a better job managing itself than I can. This is with a 5.3 CC SB 4x4 with 3.42 gears and the crappy factory Goodyear tires. Anybody else seeing anything like this?

[dntlkbak]

Yep, My 2014 Silverado is the same as well as my 2012 F150 EcoBoost, of course the EcoBoost can't touch the Silverado in economy though.

[dat329]

It's the same for me. I have the 14 SLT CC with the 3.42 gears. I get great highway miles about 20-25mpg on cruise and worse if I try to control it. In town, I get 14-16 if I'm lucky. I try to be very easy on the throttle, but I still get crap mileage driving in town.

 

I've use regular gas during the week and preimum during the weekends when I tow and I see no difference in mileage either. While towing I get 10-14 mpg depending on topography.

[johne]

Best I have ever seen on mine was just under 21 when I first got it...running on cruise control down flat highway at 55 with windows up, a/c off and just me in the truck and no cargo. I just don't see how these would ever see the rated 23 mpg. I am getting more like 16-17 mpg at best driving normally with cargo making highway runs down to the beach just about every weekend. It is really not much better than the 05' Tahoe we just got rid of. The main reason I went chevy was the advertised fuel economy. Pretty dissappointed. I should have just bought a preowned previous gen and would have had a better built vehicle with about the same fuel economy for less money.

 

My friend is getting 16-17 highway mpg on his 07 1500 4x4 with leveling kit and 33" bfg load range e tires. The new gens only seem to actually only get about 2 mpg better at best in reality. On my previous truck, I always used to hear people saying they were getting well over 20 mpg in the same 3/4 ton Dodge diesel 4x4 I had. I always called bs...The best I could ever get on mine was 17 on the highway but diesel costs more and maintenance also costs a lot more on a diesel. However, I could most likely have put my silverado up on the bed of my dodge if I had a flatbed and tow 3 or 4 more on a trailer at the same time and still get 12 or 13 mpg which is really not that much worse than what I'm getting every weekend in my brand new truck that is supposed to get well over 23 mpg highway. And I loved the cruise control on that truck, used it all the time on the highway.

[Luster]

This is interesting... I've always been from the "I-can-control-it-better-than-cruise" camp.

 

But now you've got me thinking.....

 

Right now my city-only average is about 16.8.

Highway-only - 21.3

Combined - 18.0

 

I'm going to try the cruise for the next several days and report my results back here.

[fondupot]

I used to be able to get better mileage in my 2005 1500 Sierra without cruise - if I tried hard it would get 19 on the highway driving it easy. With the new 14 I get about 17 with me driving it easy, but with the cruise I managed to get 21.4 (according to the DIC) on a 50 mile highway run between 65 and 80 (I-35 with moderate traffic). The DIC reported 17.8 on the tank and actual was 17.5, so it is reporting pretty fairly close. Seems like the throttle by wire system does a better job managing itself than I can. This is with a 5.3 CC SB 4x4 with 3.42 gears and the crappy factory Goodyear tires. Anybody else seeing anything like this?

 

Youll get better mileage with cruise on with these trucks because it keeps the throttle even which helps engage AFM more often. If you try to control with your foot you are gonna put it into V8 mode more often and use more fuel.

 

I dunno how to explain you getting better mileage in your 05 with the cruise off tho. thats just wierd.

[00Silverado4x4]

I have always gotten better mpg's with cruise as long as it's flat highway driving. I'm just too impatient most times to allow cruise to do it's job efficiently.

[Mickey_D]

 

I dunno how to explain you getting better mileage in your 05 with the cruise off tho. thats just wierd.

The 05 did not switch out from 8 to 4 cylinder mode. I would let it drop off speed going up hills and pick it back up on the downhill when the cruise was not being used. The cruise on it would let it bounce around by a couple of mph, so when going up a hill it would drop off to it's lower limit, and to try to catch back up, it would down shift and race back up to where it was supposed to be. It worked OK on flat ground, but any sort of hill got it flustered. Our 07 Tahoe is better, but the 14 really nailed it.

[fondupot]

The 05 did not switch out from 8 to 4 cylinder mode. I would let it drop off speed going up hills and pick it back up on the downhill when the cruise was not being used. The cruise on it would let it bounce around by a couple of mph, so when going up a hill it would drop off to it's lower limit, and to try to catch back up, it would down shift and race back up to where it was supposed to be. It worked OK on flat ground, but any sort of hill got it flustered. Our 07 Tahoe is better, but the 14 really nailed it.

Your 05 did not have AFM

[GearheadSS]

It's the same for me. I have the 14 SLT CC with the 3.42 gears. I get great highway miles about 20-25mpg on cruise and worse if I try to control it. In townI get 14-16 if I'm lucky. I try to be very easy on the throttle, but I still get crap mileage driving in town.

 

I've use regular gas during the week and preimum during the weekends when I tow and I see no difference in mileage either. While towing I get 10-14 mpg depending on topography.

You're probably not doing yourself any favors by switching fuel grades. The L83 is designed to run on regular. GM reps and trainers always told us that there's no advantage to using a higher grade fuel in their vehicles that aren't designed for it. It's different for performance cars like Camaro V8 and Corvette because those cares are designed to run on premium.

 

As for my mileage, I got 23mpg on a 30 mile trip with the speeds between 65-82mph. My truck is a 2WD crew cab 5.3 with 3.42 axle ratio.

 

I have noticed that I can't get the same mileage on the 14s that I got when the trucks first came out last year. I got 24.3 mpg on the same trip last year in an identical truck.

[dat329]

You're probably not doing yourself any favors by switching fuel grades. The L83 is designed to run on regular. GM reps and trainers always told us that there's no advantage to using a higher grade fuel in their vehicles that aren't designed for it. It's different for performance cars like Camaro V8 and Corvette because those cares are designed to run on premium.

 

As for my mileage, I got 23mpg on a 30 mile trip with the speeds between 65-82mph. My truck is a 2WD crew cab 5.3 with 3.42 axle ratio.

 

I have noticed that I can't get the same mileage on the 14s that I got when the trucks first came out last year. I got 24.3 mpg on the same trip last year in an identical truck

I read somewhere that premium fuel was recommended but not required. Maybe that was for the 6.2 engine. I'll keep this in mind the next time I fill up. The difference between regular and premium is about $.50 per gallon and I rather keep that in my pocket since I've been filling so about every 3-4 days.

[rboksilver]

I think the cruise does a better job also. It seems to stay in the V4 mode longer. I got 22.4 for the last 50mi on my screen using cruise.There were a few hills. 2WD 5.3 CC still new, less than 1000 miles.

[2017SierraSLT]

I always get better mileage not using the cruise.

[PMattras]

On the back roads with a lot of up and down hills (50 MPH average), I get better gas mileage without the cruise. On highways with mostly straight I get better gas mileage with the cruise.

[thefishhawk]

I know there are lots of threads on this but since it came up here I'll ask, premium vs regular..a little twist since I live at altitude though.

 

Here in CO our regular gas is 85, not 87. From what I've read the altitude means you can drop a couple points from the octane rating. But if the engine is tuned to run on 87, what I should I really do?

 

I had been getting great mileage my first 2k miles, had a trip up around the mountains and back over 21, towing had been good mileage too, and around town 18-19. Then I filled up with some Costco 85 and it tanked. Costco is supposedly a Top Tier vendor but it went to 16 right off the bat. After half a tank (I know that's not really a great time frame to judge it) I went to Conoco and topped it off with 91. Mileage went right back up to the 18 range, same driving to work and back everyday for a week or so. Here most of our gas is 85, 87, and 91 grades.

 

I'm leaning toward using 87 on a regular basis. thanks.