Bad Mpg?

[phonzy]

I have an 06 sierra Z71 crewcab with the 5.3L, stock sized tires, and no mods. On the highway at about 130km/h (80mph) I'm getting around 13mpg(so my indash computer says). I was told on the highway I should be getting in the 20's. Is this true? What do you usually get? I know I own a truck with a V8. What could be wrong?

[bossier62guy]

I have an 06 sierra Z71 crewcab with the 5.3L, stock sized tires, and no mods. On the highway at about 130km/h (80mph) I'm getting around 13mpg(so my indash computer says). I was told on the highway I should be getting in the 20's. Is this true? What do you usually get? I know I own a truck with a V8. What could be wrong?

 

You think you're going to get 20mpg on the highway doing 80mph.....the most I've seen out of mine was around 18mpg on the highway keeping the speed down at 65 and below. I don't think you're ever going to see 20's no matter what you do or how you drive it.

[phonzy]

Thats what I was told by many others lol. A guy I was talking to outside work said that he had the same truck as me, no mods, did the same speed... And got low 20's. Don't know if he had some serious wind push or he just got extremely lucky.. Who knows??

[bossier62guy]

Thats what I was told by many others lol. A guy I was talking to outside work said that he had the same truck as me, no mods, did the same speed... And got low 20's. Don't know if he had some serious wind push or he just got extremely lucky.. Who knows??

 

I'm not buying it.....if you're running that engine over 2000 rpm's you're killing your gas mileage.

[phonzy]

Got me there! Thank-you for your help! Much Appreciated!

[txab]

What could be wrong????? Your foot!

 

That 20 mpg you mention is probably at about 60- 65. As stated at your speed your churning that engine well over 2k RPM. Your mileage drops like a rock over 2k RPM.

 

Does you friend have the same exact truck?

[brims]

I have an Aeroforce Interceptor, 1 of the features is estimated HP. When doing 60-65 it calculates about 40 HP, when doing 75-80 it calculates about 70 HP. So you're using a lot more fuel to keep it going that fast.

[rodram]

the difference in fuel economy between two identical trucks could be:

- the driver; or

- the rear axle gears if you have 4.10's and your buddy has 3.42's (... or 3.23's) then his truck will get better fuel economy, when the driving conditions and driver are the same

 

.. for those guys south in the US... phonzy here in Saskatoon is talking about miles per (canadian) gallon.... (that is about 20% bigger volume than a US gallon)

 

.. to phonzy ... if you drive your truck at 130 km/hr all the time... you will eat fuel (at that rate you might as well have a HEMI), you will continue to get speeding tickets (they get expensive after a while), and you will be a general danger to everyone else on the road.... SLOW DOWN!... your profile says you are only 19... you obviously still have a lot to learn about vehicles (and life.)

 

.. in my old 97 5.7L Vortec xcsb (213,000 km and with 3.73 gears) I get 21-22 mpg (canadian) on the highway and 15-16 mpg (canadian) overall average (over the past 12 months) city/highway/winter/summer.

[mrhook]

Well, I'm from Manitoba canada, and I have a 04 sierra z71 with 5.3 ext. cab and on the hwy doing 100km/h I am getting 12-13L per 100 km. Not too sure what that is in gallons but wasnt too bad I thought. Doing 110km/h makes it burn about 2 L per 100 km more. Hope this helps? But I hear ya, sometimes ya just gotta put the hammer down and wind her out!! lol I love passing folks haha

ps I also have 4.10's in the rear.

[rodram]

well mrhook.... you are doing pretty good on fuel economy... driving at the reasonable speed of 100 km/hr

 

take your 13L per 100 km ..... and then take 282 divided by 13 = 21.7 mpg (canadian)

 

conversion works the same way back if you have 20 mpg then 282 divided by 20 = 14.1 L/100km

[HawkScot]

Are you due for some maintenance, perhaps air filter needs replacing?

[phonzy]

Thanks Rod R for telling me that I need to "Slow Down". I havent gotten a ticket yet, and I am a safe courtious driver in the city. My response to the slow down, learn more about life and vehicles... I am 19...Think about it...(Just my 2 cents) But thanks for all the technical ideas to look into. To Hawkeye, I just replaced my filter to an AFE. Older one was a little dirty. I guess I'll find out what I get when I have to drive 400km to pick up my sled! Thanks for all the inputs!

[mrhook]

well mrhook.... you are doing pretty good on fuel economy... driving at the reasonable speed of 100 km/hr

 

take your 13L per 100 km ..... and then take 282 divided by 13 = 21.7 mpg (canadian)

 

conversion works the same way back if you have 20 mpg then 282 divided by 20 = 14.1 L/100km

 

 

 

 

Thanks Rod R I thought it wasn't to bad. Just wasn't sure how to convert it.

[phonzy]

Looks like the AFE drop in filter did some work on the MPG. Gave me a little better MPG on the Highway

[pm26]

I have the same truck with 3.73 gears and on the recent trip cruising at about 75 MPH I got about 17 MPG highway.

 

Some things to do to improve the fuel economy:

 

1. use cruise control wherever possible

 

2. keep the speed down to about 75 MPH. My truck does 2,200 RPM in top gear at that speed.

 

3. get a toneau cover for the bed

 

4. do not stomp on the gas pedal when accelerating - do it gradually

 

5. keep the tires inflated to at least 36 psi

 

6. experiment with different brands and octanes of fuel - some fuel have additives that can boost your mileage some

 

7. do not use A/C if you do not have to, but it is better to use A/C and keep the windows closed (Open window = a lot of aerodynamic drag)