Help: poor mpg

[Scottd]

Good evening. I have an 08 GMC 2500 HD. Truck has 103k miles 4x4 loaded with all options. It has a superchips programmer and K&N air box. No aftermarket exhaust. Problem is fuel mileage. Sucks.1496 mile rndtrp to Houston pulling a 20 ft trailer and coming back with approx. 1600 lbs truck got 11-12 mpg. My 05 got much more than that. Only thing I see wrong is the engine symbol is on. Checked and needs number six glow plug. Had oil and ff changed. Dash says 28 pc oil life and 0 pc ff life. had ff changed again but didn't reset computer. Truck runs perfect , plenty of power ,but lowsy fuel mileage. Was told truck has gotten over 20 on road empty. Absolutely nothing out of ordinary. Take off good as it rained all the way back and forth. av 60 mph. Load level. I have no idea. Any suggestions? Truck belongs to my brother and I am thinking of buying. Not like this.

Thanks for any input,

Scottd

 

[ty_LBZ]

Remove the programmer

 

[Dirtymaxx03]

Whens is the last time the fuel filter was changed?

 

[melms23]

new air filter and fuel filter is the easiest and cheapest way to get better mpg. How much air in the tires? What sort of trailer, does it push a lot of wind?

also, the dpf uses fuel to regen.

I would think you should be closer to 15-16 if you are truly driving 60 mph.

 

[mike diesel]

It's anyones guess what the truck will get for fuel mileage. Just cause joe blow says he gets 20mpg in his doesn't mean you will.

I average 11-13mpg in the winter in my truck...empty, no trailer.

 

[CaptPhil]

Ha I hear that all the time about guys getting 22-25mpg. Yea not happening.

My wife drives my stock truck and gets 18-19mpg. I average about 15mpg. She drives it like an old woman lol.

Sent from my SM-G900V using Tapatalk

 

[countrycorey]

I have been averaging ~17.5 on a tow tune with the mods in my sig.


Corey

 

[ty_LBZ]

This winter fuel brings down your MPG too. I average 17-18

 

[Mpsoldier]

Driving from ct to Florida hauling a 23' boat 4 people in the truck and 2 Harley's in the bed I got best of 14.7 doing 80mph