One of the biggest reasons i traded from my 8.1 to a duramax was for the mileage. I don't drive longs trips or anything, but i still expected better mileage than 12 or 13. What needs to be done to improve this.

Hey Jeremy. Unfortunately, it's the longer drives where you'll see the biggest fuel mileage gains. I owned an 8.1L for 4 years and the best fuel mileage I could get at 65 mph unloaded was 12.5 mpg (in-town was around 9.0 mpg). With my LBZ, my last trip up to NorCal (689 mile round trip), I got 21.2 mpg at 65 mph. However, my in-town/short trip mileage with my LBZ is around 14.0 mpg Summer/12.0-13.0 mpg Winter.

Hey Jeremy. Unfortunately, it's the longer drives where you'll see the biggest fuel mileage gains. I owned an 8.1L for 4 years and the best fuel mileage I could get at 65 mph unloaded was 12.5 mpg (in-town was around 9.0 mpg). With my LBZ, my last trip up to NorCal (689 mile round trip), I got 21.2 mpg at 65 mph. However, my in-town/short trip mileage with my LBZ is around 14.0 mpg Summer/12.0-13.0 mpg Winter.

X2

This is pretty consistent with my experience. Around town driving, specifically taking off from a dead stop KILLS your MPG's. Remember, you are trying to move 7000 lbs. from a standstill. It simply takes a lot of energy to do that. I have noticed I am much more attuned to traffic and try very hard to anticipate red lights to minimize coming to a complete stop since driving a diesel, because MPG's is my biggest concern as well. Per my experience, that will make a big difference.

As vin stated, hiway mileage with our engnes is very impressive so you should be pleased when you do drive longer trips. I am currently close to 20 mpg's and as has been posted on this site repeatedly, mileage seems to improve as truck miles accumulate. I currently have 4600 miles on mine, and have read from numerous posters that best fuel economy may not be seen until 10 or even 15,000 miles is on your truck.

One other thing to consider is that I have noticed a lot of people here talk about running their tires at MUCH lower than factory recommended PSI, even as much as half of recommended pressure. I know my tire pressures are supposed to be 60 front and 71 back, and that is exactly where I keep them.

The lower your tire pressures are, the more rolling resistance the tires will have and therefore the lower your MPG's. Every little bit helps...

I am driving my second D-MAX (see my signature for details on both) these things tow better than any thing in there class, but the mpg's s_ _ ks. I guess you can't have it all. In my opinion save your

yeah, i don't really drive that far everyday or at least far on the highway to get that better mileage, but theres got to be something that will help out just a little bit.