Im running everything stock on my 99' cummins minus the intake. I get a slight sputtering when cruising around 50-60mph after I hit the pedal down to speed up. Another thing about it is that it usually only does this after the truck is "warm" .... Even then its an off and on thing... My first thought was fuel system problems, but what do I know; not all that much. Is it at all possible related to my trans?! My "drop down band" (if thats what its called) was completely busted in there. Not sure if that was the issue or not. Dont have the truck back yet so I couldnt tell ya if the trans fix, fixed this problem or not.
Sorry so long trying to cover the bases cuz I know everyone is very good about helping.

 

Guages man Guages. I don't see any listed in yer sig and especially for the VP-44 trucks they are the most important mod you will ever make. That fuel pressure guage will tell almost everything you need to know about fuel related problems just by watching what's happening with it. It's gotta be where you can see it at all times.

Hopefully this tranny repair will fix what ails ya here but if not be sure to keep us updated.

 

Here is a bit more for ya...

Gauges...
DiPricol Gauges

Fuel Pump Diagnostic...
Lift Pump Diagnostics

Then how to read error codes..
OBD II Error Codes

But your a 99 so... Here is the error code reader plus more!
ScanGauge II