This may sound silly...however I do tons of highway driving..and I always reset the average mpg as soon as I put the cruise control on..on the highway between 62-65mph(I'm in no rush to get where I'm going lol) I'll average about 16-18mpg...and I'm driving an 07 2500HD 6.0L...on the highway I'll usually be getting a consistent 16.5mpg...the moment I start driving around town and get off the highway the mpg drops to around 12-13. Sounds silly but that's what I do...idk if that helps...I went to jones beach last week with some friends...and I had 1 other person in the car and some beach chairs and a cooler full of beer...and driving there(about 55miles from where I live) I averaged 18.2mpg

 

I have an 02 Silverado 4dr with the 4.8L auto. I have about 125,000 on it with the 245/75/16 tires. I get about 12-13 in town and 17 -18 on hiway. The hiway speeds usually never go above 75. I will get the same milage loaded or empty. I've been looking at getting better milage also but so far nothing has proved to do any good. I think the only way it will happen is if I change the gearing in the differentials and at that point it will not have any low end torque for pulling. As someone else stated, the 4.8L is just too small to get it any better.

 

Not to bump an old thread but im also having some questions on my mpg. Im a little bothered at the fact that my window sticker on my 2007 2wd new body style says 16 to 20 mpg and im getting 14.5. I know its winter but i cant imagine it making a big difference. Im super light on the pedal and coast as much as possible but just cant seem to improve. I want to be around 17 city. Ive really been thinking of the edge programmer however there is a member on this board who keeps claiming they are a waste and go with a blackbear custom tuner. Im just wondering why they are so different when i can actually program the edge to my specs. Not to beat a dead hoarse but would the typical CAI, exhaust, tuner help. i guess i just want proof that the tuners worth it from people who calculate their mpg every week not just country bumpkins that think theyre getting better mpg. Also i have 373's. Thank you

 

How many miles do you have on your truck. If you have more than 80k you could replace your o2 sensors. Also try replacing your fuel filter and fuel pressure regulator. Those items are all responsible for lost economy. If your regulator is busted your not going to get the right fuel pressure to your fuel rail. Your o2 sensors give your computer the information to add more or less fuel depending on the engines needs.