Absolutely terrible gas mileage.

Savington · 06-15-2009, 03:12 AM

Just finished my first highway tow and I am seriously considering selling the stupid truck. The truck is an '05, crew cab shortbed, totally stock all the way down to the 245s on stock wheels, towing a 7500lb 26' enclosed car trailer. Doing between 60 and 65mph the entire way, I just averaged 11mpg. My damn 5.3 Suburban can probably beat that. Fresh fuel filter, too (500 miles on it now, NAPA Gold). I am getting MAYBE 14 around town, 17 unloaded on the highway cruising at 70.

What can I do to bump this up, aside from selling it and buying a Cummins? My roommate's '94 Dodge averages 16mpg pulling the same trailer at the same speed.

**mrmanners** · 06-15-2009, 04:21 AM

I am running AMSOIL synthetics, AMSOIL diesel concentrate and their cetene booster, an edge evolution tuner, with everything else stock and I am getting 16-17 around town and a little more on the highway running 70-75. Haven't towed our horses very far this summer yet and my horse trailer doesn't way abut about 9-10k.

formula455 · 06-15-2009, 05:41 AM

I just returned from weekend of camping, pulling my 28ft talon toy hauler 10,000 lbs +++ and averaged 17mpg I did limp my trans 0735 code once thou

brad6056 · 06-15-2009, 06:08 AM

Your fuel mileage is better than mine then, run 285's a big heavy steel brushguard, spray in liner, toolbox and all that junk and see what you get. Alot of these folks out here sometimes stretch the truth about their fuel mileage. Ofcourse after you dump a couple grand into programmers and chips I would hope you could get 15-16 mpg pulling a 8-14K pound trailer. Also most of these guys are in their early 20's and forgot how to do math..

**timespentsearching** · 06-15-2009, 06:36 AM

biggest thing on the LLY is you want to change the turbo mouthpiece and get a tuner. just those 2 will get you atleast in the 17-18 range.

o exhuast helps to

mijdirtyjeep · 06-15-2009, 06:44 AM

You need to fill out your sig!! Have you already done the LBZ mouth piece mod yet?? That is going to help a little as your fan/clutch will not be cycling on and off as and robbing your mileage. Second mine does not get the best at 60mph, 68mph seams to be my number but i am running 285's, just need to find the magic MPH mark. And for a 3rd I can tell you for a fact that your 5.3l is not going to net you better than what you are getting now, I have one and pulling 7k 5th wheel got 6-7mpg doing 60-60mph for 4 tanks of fuel, plus the damn thing would shift into 2nd gear just climbing overpasses. When was the last time you changed your fuel filter? Lots of little things can add up to a little loss in mpg, but honestly 11mpg with a stock truck is not that horrible, as I get 13.5mpg pulling the same load, but mine is modded, just a little, and yes I have not forgot how to do math

Savington · 06-15-2009, 12:05 PM

I have not done the mouthpiece yet, but it's on my list. Fuel filter is brand new, 500 miles on it if that. I have considered doing EFILive and an exhaust to try and bump it up a little as well.

mijdirtyjeep · 06-15-2009, 12:14 PM

Just a few more considerations, how is the condition of the trailer?? Alot of folks forget to repack bearings, check tire inflation's. I just went up to an E-Rated (from a C-rated) tire on my trailer and it pulls a lot nicer and seems to net a little more MPG as well.

**gr8shot** · 06-15-2009, 12:17 PM

If you're considering EFI Live, DO IT!! Best investment you can possibly make for your truck. I can sell you EFI, and we give you two free tunes as well with it. And I'd make a package deal if you wanted exhaust as well.

Between EFI, a new turbo mouthpiece, and exhaust, I'd think you should pick up 2mpg for sure while towing. Probably more than that empty. Let me know if you want some details and I can send ya a PM with everything you want to know.

**n0useforaname** · 06-15-2009, 12:18 PM

If I were you:

Mouthpiece (MUST DO)
Check tire pressure
turbo back exhaust
Small tune