Fuel Economy Siverado 2008/09 5.3l Only

[robertluongo]

I am a new owner of a 2009 Silverado extended cab, 5.3L, 4spd, 3.42GR. Too new to give accurate mileage. One tank mostly hwy 18.5 mpg. Would like only newer vehicles to respond. I just sold a 2008 Silverado V6 4.3L that averaged 16+ Bought the 5.3L for occassional towing but mainly reports of better mpg.

[68haywagon]

I have an 09 ex cab long bed 5.3l 3.42 rear. The best I got was 19 hwy doing 65mph all the way. Doing 75mph gets me around 17.5-18hwy. Around town I usually get 15-15.5mpg.

 

Mike

[Ryan00TJ]

Mine does what the sticker says.... 14city 20 highway. During winter drop both by 2-3mpg.

[robertluongo]

Just installed DIC. At 650 miles my combined average is 17.2 mpg. That's driving like an old man. I have been very light footed during break-in. Hoping it gets better.

[nick3941sd]

Best ive gotten so far was 15.5 But its pretty chilly where im living this time of year so every morning and usually leaving work i let it idle a little bit to warm up and im sure that sucks up some gas and lowers my mpg. Once srping/summer get here im sure it will go up some. But i have a 09 silverado 5.3 with 3.73s

[serial44]

08 Silverado CC 3.73s MPG has been disappointing. Hoping for increase once snow isn't every other day and can drive more in 2wd. Averaging maybe 12 mpg city. Took one trip 160 miles one way saw around 15 mpg hwy in 4x4 whole way tho.

[BigBlueLB756]

14.6 mpg average, but it is big as a house; Prius's tremble at the mere sight.

[ybsane]

My 2007 Suburban 4x4 gets 15 right now, come Monday it is going over to pcmforless for a complete tune and I hope to see better after that, with some performance to boot....

[robertluongo]

My 2007 Suburban 4x4 gets 15 right now, come Monday it is going over to pcmforless for a complete tune and I hope to see better after that, with some performance to boot....

 

tell us about your pcmforless tune what is the cost and what is the benefit and how is it accompliashed

[ybsane]

My 2007 Suburban 4x4 gets 15 right now, come Monday it is going over to pcmforless for a complete tune and I hope to see better after that, with some performance to boot....

 

tell us about your pcmforless tune what is the cost and what is the benefit and how is it accompliashed

 

 

 

It is similar to the Black Bear tune, but I am going for dyno time to get it down right.

[robertluongo]

What will it cost and what do you expect to gain?

[ybsane]

What will it cost and what do you expect to gain?

 

 

Probably 2mpg and better performance, you get your ECM programmed for better air fuel ratios, better WOT,timing adjustments,etc. and for the TCM, they can adjust the the torque mangement and shifting.Again to get better performance and mileage if you can keep your foot out of it...

 

Cost is available online at their website for mail order, they are 20-minutes from my house so I arranged for something more, since I am getting something done in person.

 

Rob

[ArtU]

I have a 2008 Silverado EXT cab 5.3L,4SP, 3.73 towing package.

 

It gets 15.5-16.5 combined 50% street/ 50% hiway travels to work and back.

I can get 19mpg at 55, 16.6-17.5 at 70mph hiway trips.

 

If I put my 12x7 cargo trailer on it it gets 9.5-10.5pmh at 65/70mph, 11-12 at 55-60mph now.

[emejay]

With my 07 Sierra 5.3l 2wd, I have a 60 mile one-way commute with generally light traffic and I get 21 to 23.5 MPG average for the entire tank, but I take it easy and drive about 55 MPH. Driving 70MPH sucks significantly more fuel, and I get 19 to 19.5MPH at that speed.

 

The most significant mod to improve mileage which I did was a Hypertech programer (wish I knew about Blackbear tuning before I bought it), and the second best was adding a tonneau cover (Truxedo Lo Pro). I run 42PSI in the tires (original Goodyears lasted me 88K) for another noticeable improvement. I just changed tires to Michelin, which from my research has the lowest rolling resistance. I haven't put on many miles with these tires and can't tell you if there is much improvement there. For oil , I use Mobil 1 0-30W for a slight benefit at cold starts. I also accidently damaged the black plastic air dam lip on the front, and replaced it with one off a Hybrid Sierra, which is identical except it hangs down 11 mm more. I didn't notice any change with this, but GM made only two aerodynamic changes for the Hybrid in order to improve mileage, one was the airlip, and the other a tonneau cover, so I figure it can't hurt.

 

 

 

 

[robertluongo]

You say your getting 19+mpg on the low end that is fantastic! Is your mileage being computed manually or using the DIC? You belong to a very small group. Most evhicles are getting < 18 mpg.