Only 12 mpg's!!!

[Ironmerganser]

I have the truck listed below in my sig. I am now at 63k miles. I bought the truck with 61k. I have only put 4 tanks of fuel through it, but I am only averaging about 12 mpg. Most of this has been city driving, but one tank was strictly hwy and I only got 12.3 mpg.

Is it because of my taller tires? Everything else on the truck is bone stock besides the straight through exhaust.

Any ideas would be greatly appreciated.

 

[nakahama001]

how many miles per tank do you get i have 35s and i get 284 when the fuel light come on

 

[Ironmerganser]

Well...on this last tank I had roughly 245 miles on it when the light came on and put in 21.625 gallons in at fill up. This equates to 11.3 mpg. I just thought I would get better mpg with this truck.

 

[DaveBen]

I will bet you need a new air filter. www.filter1.com is a good place to get these online.

Dave

 

[bigdiesel99]

what is your RPM when you driving on the HWY? driving 2000 or more RPM will shorten the range you can drive. Diesels dont like to run high in the rpm range keep it low and use the torque rise of the engine.

 

[John Boucher]

what is your RPM when you driving on the HWY? driving 2000 or more RPM will shorten the range you can drive. Diesels dont like to run high in the rpm range keep it low and use the torque rise of the engine.

I agree / My 03 Dually gets about 18-20 MPG on the highway when I keep it around 2000 RPMS , anything over that the MPG drop drastically

 

[fxtowboss]

I get around 12 maybe 12.5, that's with the 4.30 gears. What kind of gear ratio are you running?

 

[John Boucher]

I don't know if it makes a difference but I also put in 1/2 bottle of Diesel Klien everytank, I've been doing it since it was new.

 

[fxtowboss]

Yeah I use .64oz per gallon

 

[Maxtor]

4.11 Gears??

Your truck should get great mileage if it has 3.73 gear ratio. You have plenty of torque to pull the tall 34.6 inch tires. Dave is probably right about you needing to check out your air filter. If you had 4.11 or 4.56 gears, then 12 mpg would be about right. With 3.73 gears you should be getting 18+ mpg. My tires are 33.4 inches and I get 18.5 mpg average. You might want to stop using the Diesel Klien for a tank or two and see what your mileage is. I know when I put fuel enjector cleaner in my gas rig, mileage drops dramatically.