Gas Mileage

[dmac]

I own a 2009 GMC Sierra Crew Cab 4X4 4.8L truck.....my fuel mileage is lousy.....I was wondering, if the fuel mileage would improve as the engine breaks in? Only 1000 miles......Thanks

[j65rk]

I own a 2009 GMC Sierra Crew Cab 4X4 4.8L truck.....my fuel mileage is lousy.....I was wondering, if the fuel mileage would improve as the engine breaks in? Only 1000 miles......Thanks

 

How lousy are you talking?

[pm26]

If you see 14-15 MPG city and 17-18 HWY, this is normal. Also, winter blend gasolines cause mileage to drop in some states. Your mileage may get better in the spring and summer. Remember that a crew cab pickup is heavier than other variants.

[dmac]

I own a 2009 GMC Sierra Crew Cab 4X4 4.8L truck.....my fuel mileage is lousy.....I was wondering, if the fuel mileage would improve as the engine breaks in? Only 1000 miles......Thanks

 

How lousy are you talking?

 

 

12mpg city

[txab]

I own a 2009 GMC Sierra Crew Cab 4X4 4.8L truck.....my fuel mileage is lousy.....I was wondering, if the fuel mileage would improve as the engine breaks in? Only 1000 miles......Thanks

What mpg are you expecting?

 

 

If you see 14-15 MPG city and 17-18 HWY, this is normal. Also, winter blend gasolines cause mileage to drop in some states. Your mileage may get better in the spring and summer. Remember that a crew cab pickup is heavier than other variants.

 

+1

 

Also you've got a 4x4 adding additional weight. What are your gear ratios?

[Johnson8537]

I own a 2009 GMC Sierra Crew Cab 4X4 4.8L truck.....my fuel mileage is lousy.....I was wondering, if the fuel mileage would improve as the engine breaks in? Only 1000 miles......Thanks

 

How lousy are you talking?

 

 

12mpg city

 

 

I average 11.7 ALL CITY stop and GO...

 

6 " lift 35s 5.3

[Porter_]

it will get better as the engine breaks in. on top of that winter blend gasoline and warming your truck up in the mornings will both kill fuel economy. when i bought my truck last december and before it was broken in, i was averaging 12-13 mpg. once summer broke and i had about 6000 miles on it, i was getting 17mpg avg which i maintained all summer long.

[Bowler807]

I agree with the other posters. Your mileage will improve as the truck breaks in.

 

I also agree about the winter blend of fuel.

 

Over and above this however you need to consider that all the fluids will be colder. As lubricating fluids cool they get thicker. This translates to the unit being lubricated as being stiffer and harder to move. I'm talking power steering, transmission, transfer case, and both differentials. It does make a big difference.

[s_n_a_f_u]

new my truck did 21 and i was happy now it only does about 15 lol but i still love it lvl kit and cooper discovers stt 265/70/17 and i get the same as a guy at work 4.8 with 3.42 i'v got the same

[redvett]

Ask this question when you have about 12000 mi on your truck and no mods. You need 12K before its pretty well broke in.

[dmac]

Thanks for the feedback......Gear Ratio is 3.42....15mpg and up (city) would be great........

[frdfandc]

The biggest issue you have is the 4.8 AND the 3.42's The engine requires more fuel to get the vehicle up to speed as compared to one equipped with a 5.3 and/or 3.73's. Its all about HP/weight ratio. The less weight the engine has to push, the less fuel the engine uses.

 

My 2007, which I just got from my father-in-law, is doing 13.3 after only 3 days of driving it. My F-I-L was only averaging 11.6 mpg, but he was only driving 4 miles to work. My trip is closer to 13 miles.

 

Now the truck is equipped with a 5.3 and 3.73's but is a CCSB with a hard tonneau cover that adds a bunch of weight to the truck. Once I get everything sorted out, get the truck on synthetic oil and get a tune, the truck should be up around 15-16 mpg in the city.

[pm26]

For a 4x4 crew cab with a 4,8 liter V8, 4.10 gears would be the best choice for overall performance and economy in my opinion. I wish mine had 4.10s instead of 3.73s, and that's with a 5.3 liter and no AFM.

[bluesrefugee]

I get about 14-14.5 overall mixed city/highway (mostly secondary roads) out of my 03 GMC Z71. 5.3, 3.73 gears, 265 BFG AT's.

[FargoZ71]

I get about 14-14.5 overall mixed city/highway (mostly secondary roads) out of my 03 GMC Z71. 5.3, 3.73 gears, 265 BFG AT's.

 

 

Essentially same truck as him.. I can get 15.5-16 city in the summer with me driving it, with my g/f driving its closer to 13.. In the winter ( Averaging 10- (-10) ) I only see about 11-12 but beats getting stuck as i did in my old civic.