4.8L v8 Gas Mileage?

Khaos05 · January 7, 2007

Oh yeah, something is wrong...

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that's an understatement

SilveradoLAX7 · January 8, 2007

The website says that the 4.8L v8 will get 16mpg city and 21mpg highway...is this accurate?

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I've got a 4.8 and I can't remember ever doing worse than that. I don't have have the added weight of a crew or ext cab, but milage was one thing that I was pleasently suprised about when I got the truck.

If you do a search, there was another thread that compared the 4.8 and the 5.3 that might be helpful for you.

-Jay

GatorFan · January 8, 2007

I have a 4.8L (4X4) and love the mileage. I am running the factory 3.73 gear (G80) and 33" tires and I still get approx 18-21 Highway and 16-17 City. I also added a Hypertech III and a CAI so that might be the reason the mileage is still good with that size tire. I get better mileage than my wife's 4X4 4Runner and hers has the 3.4L V-6.

jaslo · January 8, 2007

I have a 4.8L (4X4) and love the mileage. I am running the factory 3.73 gear (G80) and 33" tires and I still get approx 18-21 Highway and 16-17 City. I also added a Hypertech III and a CAI so that might be the reason the mileage is still good with that size tire. I get better mileage than my wife's 4X4 4Runner and hers has the 3.4L V-6.

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Is your gas mileage using 91 octane?

Khaos05 · January 9, 2007

i'm thinking i'm going to just drive my truck in the city and take my fiance and soon-to-be wife's car on long trips and things so would it be worth it to get the 3.73 gears on the 4.8L?

GatorFan · January 9, 2007

I have a 4.8L (4X4) and love the mileage. I am running the factory 3.73 gear (G80) and 33" tires and I still get approx 18-21 Highway and 16-17 City. I also added a Hypertech III and a CAI so that might be the reason the mileage is still good with that size tire. I get better mileage than my wife's 4X4 4Runner and hers has the 3.4L V-6.

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Is your gas mileage using 91 octane?

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Most of the time I use 91 but I didn't see any change in mileage using 87 either.

GatorFan · January 9, 2007

i'm thinking i'm going to just drive my truck in the city and take my fiance and soon-to-be wife's car on long trips and things so would it be worth it to get the 3.73 gears on the 4.8L?

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I really like the 3.73 (G80) in my truck. I have no complaints really. The only thing is when pulling a boat (18' bass boat), the truck loves to switch gears a lot on me when driving up hills on the highway when going to the lake. My buddy has a Dodge 1500 4X4 Quad-Cab and his truck drives very well pulling the same boat and he has the smaller V-8 in his as well.

Regardless, I still like my G80. I think it's a good choice unless you're running bigger tires. It still runs like a scalded dog with 33" tires. I think if I put 35" or larger tires on it, I will think about switching to another gear ratio (4.56 or something like that).

smoke · January 9, 2007

Hello,

I have a '06, crew 4.8L with 3.23 rear. Just went over 5k miles and use 87octane. City/Urban/mixed driving, I average 15.8-17.9mpg.

Have not yet taken an extended highway only cruise. I turn roughly 1800-1900 rpm's at 70mph. I would guess I may be at 20mpg without a tonneau cover.

Be safe.

OUMike · January 9, 2007

I've got a '98 4.3L V6.....gettin about 12 MPG. Something maybe wrong?

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Yea..I have the 4.3 and around town I get about 16-16.7 mpg. Check your plugs, wires, distributor and maybe your fuel filter. My truck has just short of 210,000 miles so yours should get about the same. I see yours is a K1500, so I'd expect 1-2 mpg worse than mine. But 12 is terrible.

I'd replace PCV valve as well. Those are a couple bucks at auto part store.

wriley4409 · January 10, 2007

The website says that the 4.8L v8 will get 16mpg city and 21mpg highway...is this accurate?

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smilie

I am able to match the EPA estimates with my 2007 Silverado Classic Crew Cab, but only by driving very conservatively. It would be very easy (and fun) to drive this truck harder and get 12-13 MPG in town, versus the 17-18 that I am able to get by driving more conservatively.

My first addition to the truck was a Scanguage (http://www.scanguage.com/) real time PCM monitor, and this really helps to learn how to drive the truck to get better mileage. It is downright scary to step on the gas hard and see the mileage drop to 1-2 MPG!

Happy Trucking!

swat · January 11, 2007

Hi, Im new here but i already know that something is wrong since i only get 13-14 mpg and i drive a regular cab 1999 4.8. I have 285 cooper ST tires on it but that still sounds horrible compared to what you all are saying.

Is this normal for the tires and 116k or do i still suck?

pm26 · January 11, 2007

Hi, Im new here but i already know that something is wrong since i only get 13-14 mpg and i drive a regular cab 1999 4.8. I have 285 cooper ST tires on it but that still sounds horrible compared to what you all are saying.

Is this normal for the tires and 116k or do i still suck?

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It all depends on the way you drive, condition of the vehicle and the engine, and the type of fuel you use.

Using heavy weight oil like 80W140 in the rear differential in colder weather may hurt your mileage by as much as 2MPG.

Using cheap no brand name 87 octane gas can lower your mileage.

A malfunctioning EGR, heavy carbon deposits on pistons and valves, valve can also cause a drop in fuel economy.

Using oversize tires like you are, has the net effect of using higher gears, which may lug the engine if heavily loaded. I would not use anything but stock tires with a 3.23. or similar axle gear ratio.

GatorFan · January 11, 2007

The website says that the 4.8L v8 will get 16mpg city and 21mpg highway...is this accurate?

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java script:emoticon('')

smilie

I am able to match the EPA estimates with my 2007 Silverado Classic Crew Cab, but only by driving very conservatively. It would be very easy (and fun) to drive this truck harder and get 12-13 MPG in town, versus the 17-18 that I am able to get by driving more conservatively.

My first addition to the truck was a Scanguage (http://www.scanguage.com/) real time PCM monitor, and this really helps to learn how to drive the truck to get better mileage. It is downright scary to step on the gas hard and see the mileage drop to 1-2 MPG!

Happy Trucking!

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How did this scangauge mount in your vehicle? Is there a pod that comes with the tool or did you have to buy it separately?