I have a 2006, GMC crew cab, 4x4 short bed w 18k miles. I am having a hard time coping w/ 8mpg towing my almost empty 30ft. toy hauler (7000#'s) I am a GM guy all the way, but at this point I am losing my patience with this truck. Any ideas???? (BTY- that is calc'd mpg)

Thanks,
PJR

I was wondering how fast your traveling? I have a similar set up and if I run 70mph or faster thats about what I get. If I slow down to 65mph then I get 10-12mpg. A few miles per hour seem to make a lot of difference. My old gas burner would get 5 to 8mpg under the same
load so this is a big improvement for me.:driver:

Speed did not appear to be a factor. My trip took me from So Cal to McCall Id and back. On the way, I went between 60 and 65. Coming home, I was 65-70. No real difference in MPG. I reset the on-board unit when I started the trip. 230 miles later, it was indicating 7.7MPG. Calc'd was 7.9mpg. As the trip went on, the indicated MPG never went over 8.1 and calc'd was 8.

You running the tow/haul mode or not? What kind of grades you pulling up? If it's a flat run(prolly not) then your mileage shouldn't be that bad. But a lot of hills kills mileage, I don't care what it is. Is your truck stock or what have you done to it? Fill out your signature and we might be able to help a little more.

Mine gets about 9 mpg towing 30ft tb 8k from yuma - san diego through the mountains, all my friends have Fords pwr strokes they only get 10 mpg when towing similar toyboxes. They are only pushin 300hp (stock) vs lbz 360hp. I think that extra power kills the mpg.

Sell it and buy a gasser I'm sure it would get better mileage and pull better too. Speed is a factor see what you get at 55 mph.:D

I have a 2006, GMC crew cab, 4x4 short bed w 18k miles. I am having a hard time coping w/ 8mpg towing my almost empty 30ft. toy hauler (7000#'s) I am a GM guy all the way, but at this point I am losing my patience with this truck. Any ideas???? (BTY- that is calc'd mpg)

Thanks,
PJR
I get the same with my 30TT 8k and I even have a program and I run acetone

I use to have a gasser (same truck) it got 6-7 when towing and the best hwy was 12.8mpg. If you want good mpg then get a older lb7 truck.

Sell it and buy a gasser I'm sure it would get better mileage and pull better too. Speed is a factor see what you get at 55 mph.:D
it will get the same milage because my 04gasser did with the same trailer but my power now is night and day

Well at least you can pull a steady 60+. I bet a gasser won't even hold cruise at that speed up any major hills.

I just got done hauling about 1000lbs in the bed and pulling a trailer which wieghed around 5000lbs with 4 passengers and got on average 12 mpg with cruise on 70mph. Going to Spokane is more uphill than coming back, so I got better on the way back, around 14+mpg.

But hey if your not happy sell it, take the loss on depreciation and buy a gasser and come back to the site when you decide to trade back and take another loss :p:

2007 lbz cc 4wd, interstate speeds,80mph+ mine gets less than 10mpg, and that was pulling 2 sportbikes on a small trailer with 325/18 tires and bully on extreme, no cat, full mbrp. Mileage is pretty good considering how much power this thing has. My 06 dodge was way better in mpg department, my .02. D.

What kind of milage do you get empty? From what I have found the Duramax varies alot empty verses towing. You should still get a couple MPG better pulling than a gas burner and several better empty. Plus alot more torqe. I get 18-20 empty with no trailer and 7-14 towing depending on trailer size and headwinds.

Sorry to hear you are not happy with your mileage while towing. I have a small 6,000 lb travel trailer and driving between 60 and 65 I get about 12 MPG on a good day.

Even if your mileage comes up to 12 like mine, it will make little financial difference unless you tow for a living. HaulinRV comes to mind. Anyway, forget about the mileage for a while and focus on all those other things that you like about your new truck.

I like the fact that I can smoke the tires while towing my trailer. Pretty cool huh?

Good luck!

I'm on the road now, towing my 16,300# fifth wheel (18,700# GVWR) to Branson and am posting from a campground's WiFi tonight. Yesterday we averaged 10.1 mpg, hit some hills today and dropped to 9.8 mpg. About what I'd expect with this size load.

Fuel @ the 2 Flying J's we stopped at was $2.669 and $2.679. Works out to about 26 to 27 cents per mile towing. Costs 15-16 cents a mile empty so trailer is only a 10-11 cent/mile penalty.

What kind of milage do you get empty? From what I have found the Duramax varies alot empty verses towing. You should still get a couple MPG better pulling than a gas burner and several better empty. Plus alot more torqe. I get 18-20 empty with no trailer and 7-14 towing depending on trailer size and headwinds.


Ditto

Just a small suggestion, add a cheap 4" exhaust, best mod for the money for my truck, under all towing conditions. Picked up 'bout 1-2 mpg. Other than that, I am on the same page as most, don't really care about the mileage, this thing rocks towing. I'll never buy another gasser.

I have a 2006, GMC crew cab, 4x4 short bed w 18k miles. I am having a hard time coping w/ 8mpg towing my almost empty 30ft. toy hauler (7000#'s) I am a GM guy all the way, but at this point I am losing my patience with this truck. Any ideas???? (BTY- that is calc'd mpg)

Thanks,
PJR

Have you changed tire size?



I use to have a gasser (same truck) it got 6-7 when towing and the best hwy was 12.8mpg. If you want good mpg then get a older lb7 truck.

Or a Cummins:p:

I'm on the road now, towing my 16,300# fifth wheel (18,700# GVWR) to Branson and am posting from a campground's WiFi tonight. Yesterday we averaged 10.1 mpg, hit some hills today and dropped to 9.8 mpg. About what I'd expect with this size load.

Fuel @ the 2 Flying J's we stopped at was $2.669 and $2.679. Works out to about 26 to 27 cents per mile towing. Costs 15-16 cents a mile empty so trailer is only a 10-11 cent/mile penalty.

I can pul high profile 34ft 5ers and always get better mpg than a tt. And toy hauler tt always get the worst.

Awww come on "haulin" you just need to break it in! need to get some miles on her before the good MPG start to show.
LOL

Dont sound bad to me. We pull a 30ft (26A) bumper pull toy hauler and get usually around 10 mpg mark. Drafting makes a big difference and speed kills it!! Might try a camper shell to get the air up and over... Haulin Rv is right a 5fer will pull easier, its not the weight, its the 3 sheets of plywood sticking up behind your tailgate saying "wind stop here" . lol

I just pulled my 39' 13k toy hauler 5er this weekend for the first time to the lake. about 400 miles round trip at about 70mph, got 7.5 mpg. I have 6500 miles on the new truck, 07' classic. My last truck ( 04.5 LLY) would have gotten 10-11 mpg, so I figure I just need to break in more and then maybe get an exhaust. I can say that stock she has alot more torque than my last truck when it was stock.... by a long ways. No problem pulling the 5er in stock form, but it will be better with an 4" exhaust I am sure.

Even unloaded running 60-65 mpg, the best I can manage right now is about 16.5 mpg, with the OD on, running quite a few hundred rpm's less than my old truck. I am disappointed, but I am going to wait until she is broke in all the way before I comment further. Also curious about that 4" exhaust, how it will affect things after installed.

I have the 5'ver in my garage pictures. I'm at Buckeye lake and came through PA on route 80 to Ohio for my son's wrestling camp. Doing 68mph I average about 9.4mpg. If I slow to 62-65 mpg usually goes up to about 10.4. A difference of a few mph can alter fuel mileage as well as head and cross winds. I would be less concerned about mpg and more concerned with how well the truck holds speed on hills and passing ability. If mpg is that big a concern try an EFI program from someone like Kennedy diesel. I run the performance tow program mileage towing is better then stock or the another program I ran, but with alot more power. Unloaded mpg has gone up to 20mpg on 70%hwy and 30% city here in Ohio.

I just went on a 300 mile trip from Dallas TX to lake Quachita in AK pulling my boat. Total weight is about 9,000 lbs. I was running 75-80 and at times up moderate grades. My average for the whole trip was 10 mpg hand calc.

Unfortunately I found at 55 you see a big improvement. If you want to go faster you going to pay for it. Just try it, you'll be amazed on how much better the fuel economy is.

awwww, come on! Do 80 and get there faster. Who needs better than 7MPG anyway? :D

@ 55-70 I still get the same milage 8-9.5 MPG, and I have a topper on too, with the tonaugh cover on it is the same unless I am empty then I get better with the topper then the cover and nothing, my father in law has a 38 jayco designer 5er and he is getting 12, what really burns me is I get the same milage with the 6.6TD then I did with the 6.0 gasser in the same hd cc, I even installed 3.73's in the 04HD to bring the milage up but the towing suffered

@ 55-70 I still get the same milage 8-9.5 MPG, and I have a topper on too, with the tonaugh cover on it is the same unless I am empty then I get better with the topper then the cover and nothing, my father in law has a 38 jayco designer 5er and he is getting 12, what really burns me is I get the same milage with the 6.6TD then I did with the 6.0 gasser in the same hd cc, I even installed 3.73's in the 04HD to bring the milage up but the towing suffered

You can't get the same mileage from 55-70 it just isn't possible. You go faster the engine works harder and you use more fuel simple as that.

I will give some advice which you may or may not already know. You don't have to drive a diesel like a gas truck. I had a 6.0 2500HD and you had to give it full throttle all the time to get going, up hills etc. With the diesel you really don't have to give it much throttle to make it move. With the LBZ at first I drove it hard like the gasser. Then I realized that if I drove real conservative, the performance was the same but I wasn't flooring it all the time. Easy on the throttle makes a big difference. I have a 35' enclosed gooseneck that weighs 15K lbs. that I tow daily for work.

Tim

I would have to say you should do some simple add ons. 4" Turbo Back Cat Delete, 40-60hp towing tune which I like PPE for programs, and a cold air intake wouldn't hurt either but not as nessacery as the first 2. Another one to look into is a lift pump set up. I have talked to other guys that have added the FASS setup and had another 2-4 mpg from it. Diesel, it's not a cheap addiction, but it is a fun one!

Another one to look into is a lift pump set up. I have talked to other guys that have added the FASS setup and had another 2-4 mpg from it.
I don't know how pumping more fuel to the engine would give you better fuel economy but what do I know...

07 2500 LBZ hauling my fairly loaded WW 2008 FS2300 (probably about 6000#) I average around 10 mpg casually driving (60-65 mph). Good mileage in my eyes considering how nicely it tows and runs.

Around town truck only mileage is 14.5 -16.5 depending on conditions.

I jumped 3 mpg when I traded off my 26' bumper pull toy hauler for a 36' 5th wheel toy hauler, and the 5er weighs 4K more empty!!!

BLKSMOK What does a programmer do? They raise inj pressures and pump more fuel right? But you also get better fuel economy, correct? Then why wouldn't a FASS system that pumps more fuel, sepperates water and air from the fuel give you more power and better economy? I could be wrong and if I am please correct me.

I think programmers gain you fuel economy by adjusting timing and pulse width. Yes they raise rail pressures and move more fuel to create more power when you run the higher levels but in the economy modes, I think it's mostly timing, pulse width, and boost adjustments. I can understand how adjusting how and when the fuel is delivered could gain you more MPG but just putting more fuel to the engine...I don't see how that would gain you MPG. I too could be wrong.

Thanks for all of the responses. The truck is totally stock in terms of performance mods. Only have added airbags, new hitch and diff cover. I love the truck. After towing with Suburbans, E-350/V10 van, Dually Diesels and Big Blocks, it is by far the best towing vehicle that I ever owned. My driving style is not "bat out of hell, head up @$$" at all. That is the reason for my disapointment. While I was in McCall, a fellow RV'r with an '04 said he averages around 10MPG towing his 15,000#, triple slide 5er. He said the truck is stock with 75K miles. He also said that the mileage got better as the truck got more miles on it. I have 18K on my truck right now. I'll just quit whining about it and be happy with the ability to climb most grades at 60mph+ at 2/3 throttle. Thanks again.

PJR

Still should do the exhaust and 40-60hp chip. It will make a diff. I spent a little more and purchased the Magnaflow 4" turbo back, but there is almost no noise diff over stock.

I got 14-16 towing a chevy Pickup on a hauler from Fla to Pa and 18-20 Empty on cruise control. 06 3500 Chevy CC 4X4

I got 14-16 towing a chevy Pickup on a hauler from Fla to Pa and 18-20 Empty on cruise control. 06 3500 Chevy CC 4X4


On a stock truck??? You must not have tow/haul mode on. How fast are you going? 55? Wow you must have one of the best stock one out there, if that is hand calc'd.

This is the most honest mpg thread I have seen. I'm right there in the middle of the numbers. I don't know where some of these numbers I've seen in other threads come from. I have been towing various size trailers back and forth from Fl. to N.C for work and my 05 single axle rear no 4x4 didn't get any better than my dually with mods. I got bored on my last trip and played around with speed. Would reset computer and set cruise and run 30-40 miles. I can get 13-14mpg towing 10,000lbs closed trailer at 55mph. Every 5 miles per hour drops mpg. I just can't go that slow so I crank it back up to 75 (and 10mpg) and go. The saving grace is the truck will effortlesly pull what ever you want as fast as you want. Have noticed that my milage is getting a bit better as I get more miles on the clock. I guess you gotta accept the fact that to get the horse power and torque were getting out of these trucks we just "ain't going to get big mpg numbers. My humble opinion.

It does seem that exhaust and a chip will improve the mileage a little. I'll wait a while before I decide to take that step.

Again, Thanks for all of the honest responses.

PJR

Still should do the exhaust and 40-60hp chip. It will make a diff. I spent a little more and purchased the Magnaflow 4" turbo back, but there is almost no noise diff over stock.

A chip would be fine if he don't mind doing a some work to the trans.

It does seem that exhaust and a chip will improve the mileage a little. I'll wait a while before I decide to take that step.

Again, Thanks for all of the honest responses.

PJR

I would just do a muffler delete on the stock system unless you don't mind losing the cat, a catback on a newer truck isn't worth it IMO.