i went today and picked up a new trailer in elkhart,and wondered about mpg.i filled in town,by the way it was 3.96/gal....nice.and directly got on the highway,and drove like grandma.i triple ck'd the od and its right on,so i went 54.5 mi,and filled at the exit at the trailer sales,right off the hwy,3.5 gal used=15.57 mpg,ok and i went to go home w/ the trailer,24' enclosed+4'v front,empty,and i used 6.021 gal to the same place i filled at home=54.7mi= 9.08 mpg!!!! there was a decent crosswind all the way there and back,but holy crap!...now i drove there on edge 3,and back on #2tow.both ways very easy,and at 70 mph.my truck has stk 245's,and only a edge,kennedy boost valve,and opened air box. i feel like crap,and might buy a dodge,unless someone can explain this poor mpg.HELP or i might sell,this is bad,and fuel being 4 buck/gal,might use the 6.0 truck instead.....any help would be great.thanks.

i forgot to add i have a full 4" exh,and no winter front,and the temps are around 180-185 or so,should they be higher? maybe a t-stat change??

I got 12 mpg on back roads pulling a 25ft gooseneck with 2 off road golf carts on it going 80 the whole way. :)
Somethings wrong, you shouldnt have 9 mpg...

I wouldn't let one load ruin your day and I understand about fuel prices, My fuel bill was almost 2k last month with out towing, anyway I would check that there isn't anything obviously wrong, trailer brakes dragging or something like that, Some fuel has poor cetane rating which will affect milage (so I have been told) There are days that I get 25 mpg empty and some days only 20 empty, Towing my tractor to the shop I get about 17mpg but again that is a small tractor on a 16' dual axle trailer. I would tow and see if something gets better or maybe use the 6.0 to compare.....just my 2 cents

It seems like everytime I've towed in a crosswind my mileage has sucked. I'd give it a few more pulls in varying conditions before getting rid of it.

yea the crosswind was a brute,and once i went north,things seemed easier.im wondering about the injectors,but i dont have any of the troubles.it has power,on the way home,after the final fill,i put it on 3 and stood on it,and it was at 85,right now.i might test the mpg another day,i really like the truck,except the mpg at times.any typical problems w/ lb7's when using a lot of fuel?thanks guys

I tow 7k get high 14's into 15's. empty, being easy on it with setup as in sig, six gun on 4, quad at 50hp, town get 18, hwy 22

I have a 2007 classic, 265 75 R 16 tires, no tuner. I pulled an enclosed snowmobile trailer from iowa to northern wisconsin and back last week. 22 x 8' plus the V, 6'6" ceiling on a deckover, total trailer weighed no more than 4600 lbs. temps from 0 to 20 degrees. mix of interstate driving 70-75mph and highway driving 60 mph.

I was disappointed to see when I got back that the mileage showed 8.2MPG!!. So I hand calculated it and it was actually 7.3MPG!!!

My last trip pulling my 27.5 foot 5th wheel, 9500 lbs. to Maine and NH, I averaged 13.5 mpg over 900+ miles with a little no-towing miles thrown in. This was hand calculated with Edge set on 1. When I got home from the trip, I found out that my injectors had gone bad and the crankcase was full of diesel. I regularly average around 13 mpg towing to RI and back.

If you were towing and only up at 180F, then that is too cool for good mpg. A partial block of the radiator may help. the full winter grill cover may be too hot.

The wind may have made the truck pull like it was going 80-85 mpg - econ goes in the tank with a head wind

The fuel you got may have been low cetane, low energy winter blend.

You should also change the fuel filter, air filter and clean the air flow sensor - those things may help a bit.

In general, the duramax seems to be tuned to have best mpg empty. Adding a load, even a small one seems like it puts the engine controller into a rich mode and mpg plummet.

jb

my 03 dually pulling my 30' GN with my 2002 crew cab on it plus weights, about 26k total. i usually get about 11 or 12 but i drive 75 or so. empty its about 16 but i don't drive it easy.