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Discussion Starter · #1 ·
What MPG does everyone average on their LBZ? I just got my '06 about 6 weeks ago, and it's a great truck, but I'm getting nowhere near the 18mpg city/22mpg highway the previous owner claimed it was getting. Hell, it's getting worse mileage than my '01 5.3 did. I did a full fill-up and am waiting for it to come down to get a better idea, but when my fuel is sitting at half-tank and only about 140 miles on the trip (all light footing except for a structure fire last night, but that was only about 6-7 miles and not even pushing hard) which is not a good sign. I did have a fuel line leak when I got the truck, but compression fittings fixed that issue, I'm just starting to wonder if the fittings are failing & I should just have the line replaced..truck only has 156k on it and the previous owner did all the necessary maintenance (every little thing, oil change, fuel filter, etc)
 

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Discussion Starter · #2 ·
Hate to bump this up so soon, but I'm starting to get bugged with the truck. I've only averaged about 12mpg with a light foot (only had two calls on this fillup and I was only a couple miles from the station, so it wouldn't have put that much of a strain on it. No towing either. What should I start looking at?
 

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We need to know more about the truck.... tire size rim size lift?

Some things to look at... wheel hubs, quality plugs and wires as in Ac Delco not bosch.... iridium not platinum

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gmcultr said:
We need to know more about the truck.... tire size rim size lift?

Some things to look at... wheel hubs, quality plugs and wires as in Ac Delco not bosch.... iridium not platinum

sent from my Verizon Wireless Galaxy SIII
No plugs or wires on that one...

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Discussion Starter · #6 ·
gmcultr said:
We need to know more about the truck.... tire size rim size lift?

Some things to look at... wheel hubs, quality plugs and wires as in Ac Delco not bosch.... iridium not platinum

sent from my Verizon Wireless Galaxy SIII
285/75/16 Nitto Dura/Terra Grapplers on Nitto rims, no lift. Not trying to be a pain about it, swear, just bothers the crap out of me.
 

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Yea I read it ltz it didn't even click it wasn't right year model or anything. I was still asleep

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How are your air filter and fuel filter? Another thing is has your area switched to winter blend? Also maybe check your brakes to see if they are dragging. Any chance the previous owner had a programmer to get that kind of mileage??

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My MPG in my LLY goes way down after they switch to the winter blend diesel. I think it's mid-October when they switch.
 

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Discussion Starter · #11 ·
Update, changed the fuel filter a couple days ago, PITA to do but it was technically free since the previous owner had left a brand new filter in it, so I'd say it was due for a change. As soon as I started the truck afterwards, it seems like the truck was running a lot smoother as well. MPG seems to be doing okay for the moment, I filled up afterward and put some Seafoam in the tank, so we'll see how that helps. Air filter is fine, checked it last week and it was like new still, very little contaminants.
 

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Well tuning will help a lot with Mpgs just saying. The best way to get better Mpgs in the dmax. The tires aren't helping ether but with tuning u won't even notice I have 305-50and 285-65 for winter and my truck said 15.8 Mpgs but that went down since winter and all the warm up time. Get some Efi live and u will be super happy just make sure it a good tuning company u don't want it to be smokey it's not good for the truck.

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Discussion Starter · #17 ·
Well, here's an update. Changed the oil, got a caliper fixed (unrelated issues) had the glow plugs changed (one was failing and throwing codes) and ran some Lucas Fuel Injector Cleaner through as well, seems to be burning better so far...not by much, but noticeable at least. Tires are Nitto Dura/Terra Grappler's, 285/75/16's, so not huge tires, just bigger than average/stock. I shouldn't be only getting 10-12mpg granny-footing it though. I have a buddy with the same truck, but stock tires (and a sunroof) and the fuel turned up and its anywhere from 18-22mpg city. Something's seriously wrong, but I can't figure out what...
 

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Discussion Starter · #19 ·
Update, got the cat cut off the other day, and it was stopped up pretty good, so I said screw it and had them put a piece of pipe back in. Oddly enough the stock pipe is something like 3.25" or something, because a 4" was obviously way too big and a 3" had a very small gap between them. World of difference in the way it runs though, engine runs a lot smoother, accelerates smoother as well, and I can already tell it's burning fuel better. Next step is a full 4" or maybe 5" exhaust and tuning.
 
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