[JPL91]

Okay guys, I bought a 6.0 Powerstroke last July Fuel mileage was not good and I had to stress constantly about the junk 6.0 issues so I sold it late Novemeber 2011. December 5th 2011 bought a 91 w250 12v.. couldnt be happier with it. gets 22 MPG constantly! I have alot of buddies with 3rd gen Cummins who are reporting similar numbers (19 to 23 mpg mixed driving) (all 4x4 trucks btw) so I saved up some money and bought myself an 05 2500 4x4 with 74k miles on it. Picked the truck up last saturday 3/3/12. I wanted to be able to park my 1st gen and make it a weekend truck so figured the 3rd gen would be a nice solid vehicle for my 50 mile + drive everyday to work. Well unfortunately I am not seeing anywhere near those numbers as far as fuel mileage goes. I hand calculated 12.5 mpg on my first fill up, which consisted of driving from southern KY to the south side of Indianapolis, plus some around town driving the next day after I got home. Now because of the larger tires 325/60/r20's I did a check on my ODO and found out that for every 11.8 miles it registers, I actually went 13 miles. But even after adjusting my calculations I am still only around 14 mpg. My daily driving consists of a 25 mile trip to work and a 25 mile trip back home. I drive south in the morning as most people drive north and vice versa in the evening. My drive has 5 stoplights which you can see from miles away (flat land) and can usually time them as to not have to stop. Also, the speed limit is 55mph. I just cannot understand why this truck is getting such low mpg in such optimum driving conditions. I know the gear ration raises a big question and I do not know exactly what I've got. The sticker inside the glove box is not there anymore. I was told to look into cleaning some of my sensors such as the intake sensor, But the truck is not throwing any codes whatsoever. PLEASE HELP! Any leads would be great. I realize these trucks are big and heavy, but if so many other guys are getting high teens even low 20's hand calculated, why is my truck gulping fuel?!

 

[steelhead01]

Leveled (kills mpg)

on 325/60R20's 20" XD's (kills mpg rolling resistance and weight)

Diablo Tune (kills mpg) creates HR foot in rt foot aka hot rod foot disease expensive unless ya own an oil well producing type.

3rd Gens 04.5 4x4 and newer don't get the mileage of older 3rd G and 1st 2nd gen trucks.

if you bet 18 mpg driving like at grandpa under 55 mph on flat no traffic light freeway on summer fuel, fell lucky and blessed by the diesel gods.

these are heavier than early trucks.

read all the mpg threads on here, thousands of posts. that will keep you off the road and save fuel.

guys lie about fuel mileage and the size of their penis.

 

[Starchief_59]

I don't think anyone is getting 20+ in an 05 or 06 truck. Your mileage is low though but your tires aren't helping any.

Auto or stick?

 

[Starchief_59]

With 315/70s I average about 17.5. I've just got a smarty on 7, 5" exhaust, dual disc clutch and that's about it.

 

[JPL91]

It is an Auto. I drove a tank down to a 1/4 tank and kept the rpms below 2000 the entire tank. Still 14mpg...

 

[TurboDiesel7]

Should of gotten a small car for a 50 mile commute daily. Not a 7000 lb truck.

 

[HTQM]

17 mpg on 305/70's with the smarty on level 3. Been keeping accurate records for the past couple of tanks to see if there's any deference when I switch to EFI Live.

Same travel distance but a few more stop lights. Wonder if a tranny tune-up would help, fluid, filter etc...

 

[JPL91]

Should of gotten a small car for a 50 mile commute daily. Not a 7000 lb truck.

Maybe, maybe not. I love my trucks and it does hurt a little to spend so much on fuel, but I've tried the car thing and just wasnt into it. Just tryin to take a little of the hurt off of an expensive hobby!

 

[JPL91]

17 mpg on 305/70's with the smarty on level 3. Been keeping accurate records for the past couple of tanks to see if there's any deference when I switch to EFI Live.

Same travel distance but a few more stop lights. Wonder if a tranny tune-up would help, fluid, filter etc...

Thanks for the input. Im going to contact the previous owner and see if he has done anything along those lines.

 

[JPL91]

Leveled (kills mpg)

on 325/60R20's 20" XD's (kills mpg rolling resistance and weight)

Diablo Tune (kills mpg) creates HR foot in rt foot aka hot rod foot disease expensive unless ya own an oil well producing type.

3rd Gens 04.5 4x4 and newer don't get the mileage of older 3rd G and 1st 2nd gen trucks.

if you bet 18 mpg driving like at grandpa under 55 mph on flat no traffic light freeway on summer fuel, fell lucky and blessed by the diesel gods.

these are heavier than early trucks.

read all the mpg threads on here, thousands of posts. that will keep you off the road and save fuel.

guys lie about fuel mileage and the size of their penis.

So are you saying that if I "restore" my truck to stock and take the Diablo off, I should see an improvement in MPG?

 

[Starchief_59]

Its possible. My mpg increased with my big tires but thats because I'm not turning 2300+RPMs going down the highway like I was with stock tires.

 

[JPL91]

Its possible. My mpg increased with my big tires but thats because I'm not turning 2300+RPMs going down the highway like I was with stock tires.

Just to give you and idea, my drive is atleast 85% 55 to 60 mph at a hair over 1500 rpms.

 

[Starchief_59]

I'm not sure what kind of answer you're looking for. You should be getting better fuel mileage so something is wrong. My guess is it's your tires.

If it was my truck, first thing I would do would be to change all fluids and filters. Next would be set the truck back to stock programming and see what that does.

 

[JPL91]

I'm not sure what kind of answer you're looking for. You should be getting better fuel mileage so something is wrong. My guess is it's your tires.

If it was my truck, first thing I would do would be to change all fluids and filters. Next would be set the truck back to stock programming and see what that does.

Thanks for the positive feedback!

I just checked the pressure on all four tires. They were all sitting at 40 psi so I bumped them all up to 50psi. Next time I get in my truck I'll restore the stock settings.

My other thought was that maybe the winter fuel is killing my mileage. We have had an extremely mild winter here in central indiana. Could that have an effect?

 

[Drillbit]

Ive got a 03 so ill get a little bit better anyways but when i lifted it and put 35's on my mileage went down the drain put a programmer on it keep my foot outta it and it helps a lot but as of recently my mpg went down a lot (about 5 to 6) do a inspection front to rear any number of things can affect your mileage (for me my ujoints all around were shot my rotors were bad (causing drag in my brakes) and my fan clutch decided it didnt want to play anymore. make sure everything from top to bottom is working how it should such as clean air and fuel filters and keep your foot outta the skinny pedal

Edit* winter fuel will affect mine anywhere from 2-4 mpg as well

 

[JPL91]

Ive got a 03 so ill get a little bit better anyways but when i lifted it and put 35's on my mileage went down the drain put a programmer on it keep my foot outta it and it helps a lot but as of recently my mpg went down a lot (about 5 to 6) do a inspection front to rear any number of things can affect your mileage (for me my ujoints all around were shot my rotors were bad (causing drag in my brakes) and my fan clutch decided it didnt want to play anymore. make sure everything from top to bottom is working how it should such as clean air and fuel filters and keep your foot outta the skinny pedal

I control my right foot pretty well. I dont think it is the brakes, wouldnt I smell the brakes rubbing? I switched out the fuel filter a few days ago. I'll check the air filter next. How can i check my U joints?

 

[Drillbit]

I control my right foot pretty well. I dont think it is the brakes, wouldnt I smell the brakes rubbing? I switched out the fuel filter a few days ago. I'll check the air filter next. How can i check my U joints?

not necessarily mine werent like grinding down the freeway but enough that it affected it so i didnt get any smell and my pads were good so no screeching. get under your truck and rock the driveshaft back and forth if there is play in the u joint its a good sign they are going ( mine were so bad that if i got on the pedal or hit the brakes good i would get a pop from my rear driveshaft) another idea how are your ball joints? Hub assembly? also do you have a manual or an auto if its an auto is it slipping? when were your bands last adjusted? now dont get me wrong im not saying go out and replace all these things and throw money at it till your mileage improves just make a list of things that it might be and test each out eliminating what it couldnt be making the overall process easier on your wallet

 

[JPL91]

another weird thing ive noticed that i forgot to mention earlier, if the truck is in park and idleing, and you press the gas pedal to rev it up, when you let off it takes a second for it to start to idle down. and then when it does, it isnt...smooth i guess would be the word.

 

[bigblockSfury]

Ive got a 03 so ill get a little bit better anyways but when i lifted it and put 35's on my mileage went down the drain put a programmer on it keep my foot outta it and it helps a lot but as of recently my mpg went down a lot (about 5 to 6) do a inspection front to rear any number of things can affect your mileage (for me my ujoints all around were shot my rotors were bad (causing drag in my brakes) and my fan clutch decided it didnt want to play anymore. make sure everything from top to bottom is working how it should such as clean air and fuel filters and keep your foot outta the skinny pedal

Edit* winter fuel will affect mine anywhere from 2-4 mpg as well

I lost 4 - 4.5 mpg due to winter fuel and the truck burning more fuel to warm up. I dont let it idle more than a minute before I take off so it is not due to idling in the driveway.

OP- if you are barely turning 1500 at 55-60 mph you dont have to worry about your gearing, it is not a 4:10 :thumbsup:

 

[Starchief_59]

I guess we don't get winter fuel down here. I would die if I lost that much mileage just from seasonal fuel