MPG still terrible after 5 tanks...help

I know there are a ton of MPG threads--so if your answer is to search, I have.

I got the 255/75/17 tires with hopes of keeping mpg high.

My current setup is the 5100 Bilsteins with Hankook Dynapro 255/75/17
I've been averaging between 13 and 15 mpg since I bought the truck (stock, the best I could get was 16). I have been keeping my RPM's under 2000 even on acceleration. I don't drive over 65.

Any ideas?

I'm stumped

 

Under normal driving the truck never goes above 2k really. I get like 21 on the highway and probably 17-20 on a city/highway mix.

Something is up

 

Do you live in an area with lots of hills? I get 16MPG but drive up and down a large hill everyday from home.

I think the guys that get higher MPG are the ones that live on the flats...

Also, what's your elevation where you live? The higher you are, the lower your MPG will be.

 

I live in Annapolis MD, so I imagine that's right on sea level. There are quite a few hills on my highway driving, but not at all in town.

 

I live in an area 4300 ft above sea level, and either highway leading out of the town, has many massive steep hills to climb, so I burn alot of gas just leaving town, i try ot to have the RPM's go above 2500, but the hills are steep enough that if I want to accelerate, I have no choice, but to put it to 3000 RPM. On highway keeping the RPM's at around 2000 and doing around 110 km/h, I can get roughly 550 - 600 km per tank, but even the highways around here have large hills.

 

Do you have a GPS that gives you the actual MPH? Do you know someone that has stock tires that you can borrow for a short drive?
My factory tires only gave me 59mph at 65 on the speedo, while my 255/85/16 show 69mph at 65 on the speedo.
10mph difference over an hour is 10miles. 69miles over 3 gallons = 23mpg, and 59 miles over three gallons = 19.67mpg. 19.67/23 is 85%.
Chances are the factory mileage is inflated by small tires.

 

These trucks get shitty mileage. Mine averages 14.6. I have tried driving as easy as I can and best I ever got was 15.5. My dad just traded his Taco in on an f150. Because its better mileage, twice the power and room. My best friend did the same thing. Said it was the best move they ever made. I would do the same if I didn't need a smaller truck.

Add it it up like I did. Even if I was to triple my mileage you are only talking about a few dollars. No need to sweat a couple mpg's.

 

City, I've gotten anywhere from 12.9 to 17.4 and highway I get about 19 but I also have the 6 speed and I'm at 2500 rpm at 80 maybe a little higher

 

I average around 16.1 to 16.5 around Michigan with a DCSB. I am an hour north of Detroit. I have a lot of stop and go drivng taking kids to school and to work. Seems to do better on the highway, but I only burn just about 1/4 tank when I go 90 miles up north so I don't refill it right away. Towing my camping trailer at 65 MPH I seem to be getting 9.5. Can't complain much as this is the same as my 99 4Runner, maybe even 1 more mpg city.

 

How much of a factor does a toolbox in the back play as far as weight goes?

 

i'm gonna guess that the mileage is off.

 

Did you buy this new? What gearing do you have in the Diff.?

 

Well if you lift your truck and get a bigger tire then of course you are going to lose mileage

 

I have a tool box and a tire rack in the back of my 2009 with the stock 265's and I average 20 mpgs with a mix of hills and highway driving at 1300 feet above sea level. I've checked this quite a few times since I got it in 09 and it stays pretty close to 20mpg give or take. The lowest mpg I've had was 17mpg the best was 22mpg. 6 speed

 

Driving habits play a big part in mpg, but that doesn't seem to be your priblem. Ethanol free gas will add 2mpg, "summer blend" gas could add another 1mpg. Iron out any possible tire issues you may have, remove the secondary air filter if you can. I use 91 octane ethanol free every fill up, synthetic lubes, delete secondary air filter. I get 19-20 in the summer, 18-19 in the winter with liberal use of the 4hi option.

 

the tire size is very similar to stock 265/75/17

32PSI is what I'm running. Load range D 8 ply tires

 

I would guess your running a heavier tire since its an 8 ply. That is probably the problem. During the summer I can consistently get 19-20 mpg. I am still stock at this point.

 

In my new (to me) 2011 dclb 4x4, my last two tanks have been 18.5 and 18mpg, mixed driving. Have not been driving slowly either (75-80mph on the freeway) and i like to hit the gas a few times a tank... ...
What is the temperatures like? It is right at the freezing point here...
265/70/17 tires.
In the same driving in my 99' 4runner, (winter temps) i returned 16-16.5mpg. I'm happy with the increase.

Do you have a scangauge to monitor real time MPG's>?

 

x2

 

You guys are confusing the hell out of me! Lots of mileages but only one guy stated he had a 6 spd transmission so I know its a V6. Mileage statements for a comparison are useless without tire size, engine size and transmission. JMHO.
Tom