6.7 bad fuel mileage

[clayfairley]

I have a 2012 f-250 with 7900 miles on it. Great truck so far with now problems. The past two days i've noticed a change in fuel mileage only getting about 13mpg on highway. It almost feels like it's dragging or i'm driving in 5th gear even though i'm not. I always travel the same roads and usually get around 17.5mpg. Sometimes is have sputter or shutter in the engine around 30-40mph.

Anyone else delt with this? It is strange that it's all of a sudden loss in fuel mileage.

[mymileager]

Are you low on def fluid? Carbon build up in the system needs to be cleaned also check the egr sensor.. I was having a similar issued dealer changed my out mpg and power went came back instancly

[clayfairley]

Just filled def tank about a thousand miles ago.... What do you mean by carbon system needs cleaning?? I noticed the cleaning exhaust filter notice on dash twice today

[mymileager]

The diesels have a exhaust cleaning system the recycled the exhaust back through the motor called an egr ... When the soot builds up it causes a carbon build up in the exhaust system... That's why you have def fluid to help break that down.... I let the truck idle for an hour or two the go and drive it on the freeway, tend to get on it a little bit then let it slow itself down then get back on it and that should allow it to send some fluid through the system and blow some soot out ....

[mymileager]

By the sounds of it, seems like your newer to diesels, go into some of our forums and read up on the diesels... Heating up, cooling down, wot, eot, ect, deltas, egr's programmers, glow plugs, there is so much more behind operating a diesel then a gas motor,

[clayfairley]

Yes I am very new. I am trying to read up on everything. Just sucks only getting 12-14 mpg right now. I will try doing what you mentioned on getting on it. I hate to take it to the dealership with no dummy lights on the dash, but something surely has happened with the loss in mpg and sluggish feel.

[mymileager]

Also think about running a diesel fuel treatment through the fuel and check for water in your water separator, located on the frame rail drivers side, and also possible replace your fuel filter could be clogged or have some debris in it if you sucked anything up from the bottom of the tank of you let the truck get real low on fuel

Note: if you replace your fuel filter go buy it at the dealership, a lot of people are having problems with the after market ones where there trucks are not starting

[mymileager]

Here one of the other guys just posted this and I think it would be good knowledge for you to learn about the powerstroke motors


First Look: Ford's All-New 6.7-Liter V-8 Power Stroke Diesel Engine - PickupTrucks.com News

[Rob]

Originally Posted by mymileager

The diesels have a exhaust cleaning system the recycled the exhaust back through the motor called an egr ... When the soot builds up it causes a carbon build up in the exhaust system... That's why you have def fluid to help break that down.... I let the truck idle for an hour or two the go and drive it on the freeway, tend to get on it a little bit then let it slow itself down then get back on it and that should allow it to send some fluid through the system and blow some soot out ....

Negative... The DEF is used to reduce the NOx emissions in the exhaust, not remove soot build up. Soot build up in the DPF is removed by regeneration cycles. Regen cycles are triggered by the PCM when pressure exceeds a set value pre-DPF, causing additional fuel to be commanded, thus creating higher exhaust temperatures which in turn burns off the trapped soot in the DPF.

[clayfairley]

Originally Posted by Rob

Negative... The DEF is used to reduce the NOx emissions in the exhaust, not remove soot build up. Soot build up in the DPF is removed by regeneration cycles. Regen cycles are triggered by the PCM when pressure exceeds a set value pre-DPF, causing additional fuel to be commanded, thus creating higher exhaust temperatures which in turn burns off the trapped soot in the DPF.

What should I do in your opinion?