HELP-I have a 06 5.9, automatic, with what I would call a intermittent bucking problem. While driving, usually at highway speeds under a light load (going up small inclines or hills) the truck will suddenly "buck" almost like the fuel was shutoff instantly, it happens in overdrive, and the truck is not downshifting. It scares the s**t out of you to say the least, especially if towing, but it happens empty as well. It is intermittent, I can go hundreds of miles without the problem, then it will happen several times within 50-100 miles, it can happen at varying speeds 60-80. I have Edge juice/attitude, last week I completely disconnected it to see if that was the source of the problem, and the problem continues. No trouble codes present, new fuel filter. I am out of warranty (except for the motor) and am hesitant to go to the dealer to let them "hunt" for the problem with it being so intermittent. I don't see any changes in the RPM'S, but like I said it is instant. One post I found suggested the fuel temp/pressure sensor on the injection pump, any thoughts on this? Any way a current flash would help? Transmission? Any ideas would be appreciated.

 

Never heard of this issue. Gotta be a fueling issue though. Any fuel or rail pressure gauges? That would help.

 

I have had a similar problem on a very different vehicle. But i will give you my example to see if it sparks any thoughts.
My 85 carborated gas Jeep goes into crazy bucking every now and again. it turned out it was my electronic choke went out and would randomly close. So it turns out it was a fuelling problem. It would get too much fuel and wouldnt detonate fully. So maybe in the diesel you are getting a wrong dose of fuel.

Also with the deal, you could try to take it in with the "interest" of trading it in, you can say it has slight mechanical issues from time to time. Maybe they will take it in the back to inspect it for you before they consider "buying" it from you.

 

first check for codes being set. second read the post ( everybody read this-you may have a shorted wire ). my truck threw code for crank sensor, indicating stumble and almost totally dying, turned out to be the wire chaffing the a/c line, installed spagetti over wire. 18k later still no problems.
good luck

 

He said he had no trouble codes....

 

Mine did that!
Lift pump!
I sawed it in half to see what happened and the brushes were wore right down to nothing!
In a nutshell its a gas pump working too hard pumping the thicker diesel fuel.
The black on your fuel filter is the carbon from these motor brushes
Your pump will be running intermittant at this point.

 

The black on the fuel filter is not brush dust...LOL It is the asphaltine that is in diesel that gets filtered out...

 

Did you ever find a solution to this problem?
My truck has been doing the same thing and I have tried all the things people have suggested and it still keeps happening

 

Mine did exactly that until I found a loose negative battery cable.

 

Your computer needs a re flash with an updated tune, either dealer or if you have a handheld tuner update it with the most recent tune. Mine did this with a stock tune or with diablo predator tune that had the same issue they uplaoded a fix and not a issue since.

 

I know this is an old post but wanted to resurrect. I am having what appears to be the same problem on my 07 5.9 45k miles, however the problem only exists in low ambient temps. So far, this is what I (and the dealer) have done.
1. Changed fuel filter with a stratapore 2x.
2. Replaced lift pump.
3. Replaced tq and solenoids.
4. Replaced overflow valve and fca.
5. Test and replaced injectors.
6. Replace fan assembly.
7. Replace ECM.
8. Replaced APPS.

When the ambient temps are in the 30's it will intermittantly do what the OP has stated. Higher temps seem fine. Been chasing this problem for 13 months now. Please help.

 

check the archives on the wire chaffing the a/c line by the compressor, a single wire ,part of the 5volt power system, there used to be a sticky on it. to start just crawl under the truck r/h side, move the single wire chaffing a/c line, see if problem disapeers, i put a piece of split spaggetti over wire with ty wraps 3 years later no problem.