2006 GMC Sierra 4.8 fuel milage?

[lonely-boy]

Im trying to get my fuel milage up. Im getting roughly 14.5 to 16.5 When I first got the truck it got like 20... I have a k n n air cleaner...I use Ams oil full sythetic with filter....I tried cleaning mass air flow sensor. ran lucas fuel injector clean threw several times. anyone get an idea thanks...

 

[knuckleheaf27]

use Sea-Foam through the power brake booster vacume line.... this stuff works wonders, i have seen it first hand. if you have any questions on how to apply it just ask.....

 

[Molson02536]

Im trying to get my fuel milage up. Im getting roughly 14.5 to 16.5 When I first got the truck it got like 20... I have a k n n air cleaner...I use Ams oil full sythetic with filter....I tried cleaning mass air flow sensor. ran lucas fuel injector clean threw several times. anyone get an idea thanks...

Try replacing your Thermostat, it could be stuck and running your engine cooler then it should. This will cause poor gas mileage, the computer is set to work properly when the engine is fully warmed up. If the t-stat is changed to one that is lower, the computer sees that as still warming up and adjusts its parameters accordingly which can affect fuel mileage and catalytic converter health. Unless you are running a modified ECM which requires a lower temp stat, I would stick with a direct replacement.

I believe the Stock rating is 180 for your 4.8 Vortec. Start with this and keep us posted.

 

[webf2010]

Just try giving the car for service, if not then try changing thermostat.