OK, I've read many threads with wild claims about 20 MPG and such. I can't see how. Is there a problem with my truck?

I have an '05 4x4, Supercab with 3.73 Ltd Slip, stock tires, stock 17" wheels, and a hard tonneau cover, with an empty bed. Truck has 43K miles.

I drive like a grandma, and it pisses me off to get avg of 12 MPG combined city/hwy. I don't sit at idle, and I don't do drive thrus.

Air filter is clean, oil changed regularly, tires inflated to spec.

The only thing I can think is the damn blended gas MN requires us all to use. It's 10% ethanol, I run 87 octane. Mileage was this bad in summer weather as well.

I did a trip this summer - 99% hwy on a tank of gas, and only managed 17MPG.

Thanks for any help, pointers...

 

Yeah I've been dealing with the same thing but i just gave up caring. I average between 11 and 13 mpg. no matter what type of driving situation. The best I ever saw was 14 on the highway driving 70mph non stop through an entire tank. When I towed a trailer from Detroit to Boston (loaded on the way there, unloaded on the way back) still the same mpg. Driving like an a$$ or like a grandma, still the same. Cross country trip loaded and unloaded, same. Got my big heavy wheels and tires, exhaust, k and n filter; still the same. Oh well.

 

Its not the gas from MN. I always fuel up in Winona MN since it is 15-20 cents cheaper than here and only a 15 min drive.

I have gotten over 19mpg a couple of times when running the bigger tires and over the holidays going to the in-laws I got 20.7mpg with the stock tires. Most of the time I average around 15 with basically a 50/50 split of city and highway driving. My truck is a 04 supercab 4x4, 5.4L, 3.73ls, stock 265/75/18 Goodyears in the winter and 325/60/18 Nittos in the summer, with Edge Evo on lvl2 running 89 oct, Airaid Jr. intake, custom exhaust, Truxedo cover. My performance mods didn't affect my mileage at all, the only thing that made a difference is my 325 Nittos, they make my mileage go down .5-1.5 mpg from what I have found out.

Why does your truck get bad mileage, I can't tell you that. Each truck is different even though they may be identical as far as options, they will get different mileage. Maybe try getting the newest reflash from you dealership, or try fueling up with a different brand of gas. I know that if I fuel up at Kwik Trip I always see lower mileage numbers, so now I always go to BP, Sinclair, or Shell.

 

I have a 08 5.4 w/3.55s and beat the snot out of mine and i get 12 round town and 16-17 highway.

 

You will never get better mpg with 10%E unless you have Flex Fuel. I did some research using my own data and discovered that for a given distance, I ended up burning more gas running E90 than pure petrol (mpg*.90 vs mpg * 1).

Cool thing is, here, our corner stores (7-11) have finally got their act together and switched to only serving E free gas.

Think about it. Have you heard the reports about what the chit does to 2 and 4 stroke engines (like lawnmowers)? Cant be good for a non flex fuel vehicle.

 

usually about 12.5 around town. Flat highway about 16 to 17. That's all mine has ever got since new.

 

X2!!! I gave up a long time ago. I have tried the super premium (92) several times, absolutely no difference in mileage. I "grampa'd it", for an entire tank, using my Scangauge II to help me keep my foot out of the gas... no difference.

Mine just turned 10,000 miles this morning, so I know it is "broke in". So, I agree with brocious03, I also gave up caring....it just won't happen...at least for my Gas-Guppy.

 

Why do the force E90? Is it some environmental thing? Cause if you want to get down to brass tacks, Corn based ethanol requires more BTU to produce than it produces itself. requiring more energy to make than what it makes is highly inefficient. What the govt needs to understand is this is an energy crisis, not a Hydrocarbon issue.

 

I am supercharged and I get 10.5 to 11 mpg city?

 

winter gas is a different blend which able the truck to start easier in cold weather, but results in worse gas mileage so this time of the year thats part of what your seeing. i personally average 10-13 city on my truck w/ my 35's. my dad w/ his stock screw 5.4 w/ a gryphon averages about 15 city and has seen 22 on the interstate going 65mph. on average he gets 17-18 on the interstate going faster

 

I am averaging about 17 MPG all around - I drive 70% hiway but cannot use cruise to my advantage at times. I didn't buy my truck for the gas mileage though.

 

I have never calculated the gas mileage of my truck and I never intend to, as the knowledge of how bad it really is might interfere with my enjoyment of the sweet sounds my Magnaflow cat-back makes while I'm accelerating away from an intersection........

 

I get 15 MPG's with 89 octane in the city. If I got a set of low rolling resistant tires, I'm sure I'd see 17-19 in the city.

 

I get 13 constantly, mostly city. Dont know why it's lower compared to some others here, but it just is.

 

not wild...been there, done it many times.

might be that mine is a Flex Fuel?

with decent gas and primarily city driving I used to get 14-15 mpg...and about 18 mpg with primarily highways jaunts in the local area

on 2 long 2,500 mile trips I got 20 mpg damn near each tank @ 70-75 mph with 2 adults, 1 kid and about 500 lbs in the bed.

wierd? you must be hammering that thing all the time



I'm getting a constistent 12.5-13 mpg with 100% city only driving. I drive 10 miles/day commuting to/from work...the speed limit is 20-35 mph the entire time with 6 stoplights