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Discussion Starter · #1 ·
I have 2004.5 cc, sb, lly stock other than 285's on stock rims and mileage is horrible. and yes i added about 8% to compensate for tires. I just went on a snowmobile trip. Pulled a very light two place aluminum trailer with two sleds. and got anywhere between 10-14 mpg using cruise. Is something wrong with my truck? Had a reflash from dealer 2 weeks ago. seems to me most get much better mileage from what i have read. I think it should be doing much better than that.

ANY SUGGESTIONS, ANYONE HAVE SAME PROBLEM AND GET IT FIXED. SHOULD I TAKE IT TO DEALER...?

THANKS
 

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How fast were you pulling it? Snowmobile trailer drag more wind then you would think. 10-14 is still low but not completely off the wall depending on conditions. What do you get with just the truck flying solo?
 

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14 is good if it was an enclosed trailer, you did all right Where you using 4 wheel drive during the 10 mpg. tank?
 

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So many variables here...

The tires are eating some mileage no doubt, winter fuel has less BTUs which directly translates to less fuel mileage, and the trailer is definitely creating a lot of drag.

I'm beginning to realize more and more that within reason, weight differences aren't nearly as detrimental to mileage as wind drag is.

I don't think there's necessarily anything drastically wrong here. On my last few tanks I've only gotten 15 MPG, and that's not pulling. Combine winter fuel, more idling because it's cold, the 800 pounds of sand I have in the back plus my heavy toolbox, and really high winds--that's where all the fuel went driving 75 MPH.
 

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I wish I could see over 11 empty city driving. I'm sure alot has to do with it being 20 to 30 below and truck at high idle warming up for 20 min. And it being in 4wd all the time. And the stock 215's. Not to mention our city driving is stop and go 45mph. You never get off the gas execpt to stop. Anchorage sucks for getting good mileage
 

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I have 2004.5 cc, sb, lly stock other than 285's on stock rims and mileage is horrible. and yes i added about 8% to compensate for tires. I just went on a snowmobile trip. Pulled a very light two place aluminum trailer with two sleds. and got anywhere between 10-14 mpg using cruise. Is something wrong with my truck? Had a reflash from dealer 2 weeks ago. seems to me most get much better mileage from what i have read. I think it should be doing much better than that.

ANY SUGGESTIONS, ANYONE HAVE SAME PROBLEM AND GET IT FIXED. SHOULD I TAKE IT TO DEALER...?

THANKS
That is not bad mileage for towing. You will never get incredible mileage because of the 285's, especialy if you do predominately city driving. They do eat into the mileage alot. When I drive empty, flat, in criuse @ 70ish I get maybe about 18-18.5 Corrected by hand mileage. City, Stop & Go, around town 12 - 14, worse if i get a heavy foot. In my opinion you are okay. Winter blend is also eroding your mileage as well.

BIll
 

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10-14mpg is a 40% swing in and of itself, thats considerable without thinking its off the mark. Tighten that up first or you can't hope to compare to anything........

.
 

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Discussion Starter · #8 ·
not an enclosed trailer, just salt guard. I don't drive a lot of highway usually only city and get 15mpg, but I assumed I would get much better driving interstate. On my way home from the trip I got 10mpg on first tank, and 11mpg on the second. most of trip was either speedo reading 65 or 70 depending on if speed limit was 65 or 70, and that puts me at actual speeds of 70 or 75mph due to larger tire. I was not impressed due to the fact that this what these trucks are built for. You would think they would want higher fuel economy out of them. I thought the 285's would hinder my mpg but not that much. because you also get a little lower rpm out of them at the same time??


don't know, guess I should sell'er and get lbz...or put my 245s on huh..

thanks
 

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I'm not quite sure what you expect out of this scenario...you're driving 70 to 75 mph, have oversize tires, and are pulling a trailer.

I'm not sure where you're located, but if there's snow to run sleds, I'm gonna assume you're also running winter fuel.

I'm really not sure you can expect much more milage than this. You may be able to pick up small increases here and there, but this type of mileage is the reality for the conditions you're operating under.
 

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I thought the 285's would hinder my mpg but not that much. because you also get a little lower rpm out of them at the same time??
thanks
This may be true when running @ a constant speed on the interstate, but not true while running in Stop & Go. These tires have much more mass and more power is required to get them rolling. If you are in constant state of Stop & Go, you will use more fuel than normal becuase of the increased mass. You also state that you were running actual speeds of 70 - 75, towing. The faster you go the more fuel you use. I still think the mileages you are quoting are well within the ballpark for your truck and driving condition.

Bill
 

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probally would have got about 8 if you were lucky with a 6.0 gas with 285's in the exact same towing conditions.
 

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:exactly: To all. Speed kills mpg especially w/ 285's and trailer. Also in cold weather warm-up time and winter blend kills mpg's. I also believe that some station pumps don't read that accurately, even tho they are "certified" by some weights and measures entity. Fill her to the neck get on the Interstate, cruise steady, and re-fill as soon as you get off. This should give you a "real" highway mpg test. Remember not to do any WOT passing or other lead footing.

Also, how many miles you got? MPG's will increase after 15-20k.
 

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Discussion Starter · #13 ·
28000 miles on the truck right now. I guess I expected better out of it because I pulled the exact setup with a 1999 chevy with 5.3L gas and got 10-12mpg out of it. thought diesel would do significantly better even with the 285's. Oh well guess I am SOL.
 
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