06 fuel economy problem

[swasenko]

I am new to the forums and new to diesel trucks altogether. I just bought a 06 crew cab long box. The truck has 38k on it and alot of addons. It has a bully dog triple dog with outlook monitor. It has a K&N intake and a 4 in exhaust. If I drive the truck the way I want I get 12 mpg and if I baby the hell out of it I only get 14.5 mpg. I don't know why. Most other people I talk to say that with these mods they would expect 18-20. The only thing I can think is the truck has 325 tires on it. But with a diesel the torque should handle this big tire just fine.

Could you guys please help with how bad this is.

Thanks

[holleywood]

i have a stock 05 supercab long bed and i run 325s and i get 14 a gallon. How about cleaning air filter, changing fluids? Run synthetics

[DoubleDpsd]

14.5 on the freeway? How fast are you driving? That isn't a lot of mods and def not enough to expect to see 18-20 with a crew crab long bed. are the fuel filters clean? the torque the truck has doesn't matter against the 35's you have. It's the width and height of the tire that does effect your mileage.

[olblue]

If servicing the truck doesn't change things, swap the stock tires on and drive for a few tanks. That will tell you whether it's the tires or something else.

BTW, my 07 with Triple Dog and no other mods gets 18 maybe 18.5 on the highway at 75 as long as it's not windy. Throw in a wind and it'll drop to probably 16.5 or so.

[LvTitan]

you are fine. i drive the way i want and i continually get 12 MPG EVERY tank.
sometimes if they are all hiway miles i can see 15-16, but i have a heavy foot.

[swasenko]

I'm only driving 72mph on the highway with the cruise control and Michigan is pretty flat. No hills to deal with. I just got the truck so I am going to go through and changes the filters and fluids, but haven't yet.

18 on the highway in an 07 sounds pretty good. That I would be okay with. What setting on the triple dog do you drive with?

[Heat]

Welcome to the forum...

Mine is a bone stock '06 FX4 CC short box with 23k on it. This time of year (i.e. no A/C) I get about 16.5 around town (15.5 in the summer)... I get about 21 on the freeway at 75 mph... Towing my 5th wheel at 65 up and down hill I get between 13 and 13.5 (the trailer is almost 11k empty)... Don't know what to tell you but 325s shouldn't drive your mileage that low....

Ken....

[olblue]

Originally Posted by swasenko

I'm only driving 72mph on the highway with the cruise control and Michigan is pretty flat. No hills to deal with. I just got the truck so I am going to go through and changes the filters and fluids, but haven't yet.

18 on the highway in an 07 sounds pretty good. That I would be okay with. What setting on the triple dog do you drive with?

You might experiment with going different speeds. I don't mean varying your speed, but one trip try 65, another try 75. I found that mine seems to get better milage going closer to 75 than 65. Why? Beats me. But then again, it wasn't that big of a difference. Maybe a couple tenths. But I put on 50k a year, so a couple tenths adds up.

I phoned Bully Dog and they said that I would get the best mileage with it set on Performance because the timing is more advanced than Tow/Economy. If I have a load in the back (2200 lbs) then I set it on Tow/Economy and if I have to pull a trailer I set it on Stock. I'm not going to chance stretching head bolts. When I run it on Performance I make a point of not getting in the throttle cause I don't want the smoke plugging the cat.

[swasenko]

Mine is a bone stock '06 FX4 CC short box with 23k on it. This time of year (i.e. no A/C) I get about 16.5 around town (15.5 in the summer)... I get about 21 on the freeway at 75 mph... Towing my 5th wheel at 65 up and down hill I get between 13 and 13.5 (the trailer is almost 11k empty)... Don't know what to tell you but 325s shouldn't drive your mileage that low....

21mpg on the highway is awesome. The only difference bewtween our trucks is the longer box. I don't know what's going on. I wouldn't think the 325s would make the big of a difference either.

What other mods would you guys recommend? With the cold air intake, the 4in exhaust and cat delete, and the triple dog I thought that would be most of what would help.

[olblue]

What about a box cover?