I have a 2005 Duramax LLY (I love the truck) but i am getting terrible milage...i have 10000 miles on the truck, and the best i can get out of it is 15mpg. I had a 2001 Duramax and i was getting 24 mpg. My dealer told me that it was a problem with the LLY's, and that basically i have to deal with it. I was just wondering if everybody else was getting this kind of milage.

I have an 04.5 LLY and get about 17.5 average and 18 to 19 on the HWY.

My 01 LB7 has never gotten over 16 MPGs and it has 270,000 plus on it.

Is it a 4X4, mine is and all I get in town is 15 when I am lucky!!!!!!

Both my LB7 and my LLY weigh about 9200 empty. LB7 got 17 to 18 on hwy and the LLY gets 13 to 13.5 Only way my LLY could get 15 or better is on the back of a wrecker.

I get 12-13 city and 15-16 hwy, but I am running 35" tires.

when m/t in town i get 15-16.5 m/t on the hi-way under 65 i get 18.5 to 20 pulling my 38 ft 5th wheel i get 10/14 mpg i changed the air filter and that helped.:grd:

14 in town (7120lb curb weight 4x4), 19-20 hwy, and 15 hwy towing 6000lb. Oh, and 11.5 with a 11.5' cabover at 17,000lb combined.

Big tires, low tire pressure, weight, can all make huge differences in mileage. As can driving style.

258 mile trip yesterday mixed driving mostly highway. 18.9 calculated

I drive city mostly and I have a 05 duramax 4x4 reprogrammed and I am getting 18.2 right now and havent got on the highway....wonder what will happen when I put those 38" tires under it?

I hand calculated mine last week and running empty on the interstate I am getting 13.1 MPG. Of course I can't get regular fuel this time of year, everything is winter blend and my truck is jacked up in the air with 35's on it. I can tell my mileage has dropped since the summer. I can only figure its the blend.

I run 35's with programmer. And 330 miles on her now. So far i get 12.5-14.5 mpg under all driving conditions =( hopefully it will increase as it breaks in, and when i get the exhaust system and intake it should help a decent amount.

just filled up tonight and calculated out, 12.6, that is in town. On the highway I usually get around 16.5 to 17. Once running premium fuel I got 18.7. Wish we had it here in Libby. Sure would like to see the 20s like some of these people on here.

Gardnerteam....that was a :funnypost Anyway I have been hand calculating the last couple thousand miles and the best I can get is 15.6. Otherwise its 14.8-15.2 driving like a grandma!! The truck is not happy about being driven so sally like. But at 2.37 a gallon who can blame me....):h Oh yeah pulling the 15,000 tractor and trailer put me down for the twelves.

I also I have an 04.5 LLY and get about 17.5 average and 18 to 19 on the HWY. Sometimes 20-21 on the HWY if I stay under 60MPH.

Im getting 16 on my 2005!!!

16.5 town 18.5 highway hand calculated:) :Nothing_f

16.5 town 18.5 highway hand calculated:) :Nothing_fPretty much the same here. I also get 12 mpg when towing a 10,000 pound 5th wheel.

16 mpg in urban areas. Old 8.1 gasser was getting 9 to 10 at best.

I have a 2005 Duramax LLY (I love the truck) but i am getting terrible milage...i have 10000 miles on the truck, and the best i can get out of it is 15mpg. I had a 2001 Duramax and i was getting 24 mpg. My dealer told me that it was a problem with the LLY's, and that basically i have to deal with it. I was just wondering if everybody else was getting this kind of milage. the LLY has more hp and torque than the LB7, that's way you get less mpg, I guess GM couldn't give us both :(