I have a dodge 2500 4wd 5.9 cummins 6 Spd trans that bucks in 5th and 6th. Let me fill u in on what I have done so far. I have changed the vp44 cleaned the iat and map sensor. I have a edge juice w/attitude and I have fuel pressure changed fuel filters every oil change. My mechanic is at a loss as to where to go from here. Please help I'm getting frustrated. Oh yea I forgot I replaced the apps from Timbo.

 

unplug the edge also a cam sensor could cause that

 

I have unplugged edge and also changed cam sensor when IP was changed. Truck still does same thing.

 

That almost sounds like a bad electronics issue in the ecm or vp controls, sending bad fuel pulses to the injectors.
Is it in a certain rpm range or only in 5/6 gears?

 

All ranges of acceleration in either gear.

 

Did you replace the vp with an HO model or could you have gotten an SO version?

 

by any chance are you running bigger injecters? I am wondering if it could be a speed sensor ecm/pcm issue

 

I'm running bigger injectors. Speed has nothing to do with it. It is based on acceleration. Light to moderate acceleration it will do it.

 

Bigger injecters is whats doing it ...
lots of guys with big stick have this
my 01 has Mach 1.6 F1 injecters and does this and only in the upper gears It has something to with the cold air the colder it gets the more I notice it (more pronounced )

 

Is there any fix for this? I'm just running 75hp injectors. Any ideas would be helpful. What is causing this. You say bigger injectors and chip is causing this but I'm not the only one with a similar setup.

 

I don't know of a fix it seems to be mostly with the HOs running the engine at higher rpms helps . when my 01 just had a chip I never noticed it but when I installed the bigger injectors is when it started and I see it only in cold weather . in the summer I never feel it at all . maybe if it had less timing it would stop.I have not had a chance yet to see because I need to get rid of my catcher and install a smarty.in but I just run at a higher RPM range in winter till there is a fix

 

I noticed it more when I lived in Missouri with mild nozzlez. a little worse now in Oregon with mach 4's. but since the rebuild and the big stick Cam, this winter I haven't really noticed this (old) bucking feeling. ???? nothing electronic was touched or replaced during rebuild. so I'm confused on this. and not all HO with bigger injectors have this. wonder if more have this with a edge. I have a TST and run a smarty.