2007 GMC Sierra 1500 poor fuel economy

[Kfeds44]

First off i would like to say. i know its a truck fuel economy isnt great anyways. that is not the problem here. i just think the fuel economy should be better than what it is.

 

2007 gmc sierra 1500 NBS 5.3L with AFM

 

i am averaging about 18-19L/100kms combined City/highway and mostly highway

 

i believe this is very poor. when i first owned the truck i was averaging around 14-15L/100kms

 

 

from stock. i have added a leveling kit and 295/65/R18 tires so i knew the fuel economy was going to be worse than it was stock. my truck has not been tuned/programmed at all since ive done this work. will a superchip, bully dog tuner etc. help with this fuel economy ? or is this just how it is going to be now ? at first i didnt think a level kit and the bigger tires would affect the fuel economy this bad.

 

any help will be appreciated.

 

this is all happening driving with a light foot in town and staying around 100km/h on highway

[Nanotech Environmental]

First off i would like to say. i know its a truck fuel economy isnt great anyways. that is not the problem here. i just think the fuel economy should be better than what it is.

 

2007 gmc sierra 1500 NBS 5.3L with AFM

 

i am averaging about 18-19L/100kms combined City/highway and mostly highway

 

i believe this is very poor. when i first owned the truck i was averaging around 14-15L/100kms

 

 

from stock. i have added a leveling kit and 295/65/R18 tires so i knew the fuel economy was going to be worse than it was stock. my truck has not been tuned/programmed at all since ive done this work. will a superchip, bully dog tuner etc. help with this fuel economy ? or is this just how it is going to be now ? at first i didnt think a level kit and the bigger tires would affect the fuel economy this bad.

 

any help will be appreciated.

 

this is all happening driving with a light foot in town and staying around 100km/h on highway

Did the mileage go down as soon as you made the changes?

 

If not-

Have you still got the original steel fuel lines?

If so, check them very thoroughly for leaks. They often rust at points where they are clamped to the frame etc.

 

I had a similar issue a couple years ago on mine & it was leaky fuel lines.

 

Also, it's winter now & your mileage is going to be noticeably worse than the summertime.

[Kfeds44]

Did the mileage go down as soon as you made the changes?

 

If not-

Have you still got the original steel fuel lines?

If so, check them very thoroughly for leaks. They often rust at points where they are clamped to the frame etc.

 

I had a similar issue a couple years ago on mine & it was leaky fuel lines.

 

Also, it's winter now & your mileage is going to be noticeably worse than the summertime.

 

thanks for your help.

 

ill check it out