First, it would be really nice to know what your fuel pressure was, during this event/sputter.

CAT says anything below 35 psi, may cause issues, under a load. (if that was the issue, I would probably replace the fuel return check valve; because you already had replaced fuel filters, you said)

Next, you might have a slightly loose injector wire nut and maybe there is some arcing occurring, under a load. These are the two small nuts, on EACH injector, on those little studs, coming out the top of each solenoid. You must be reasonable gentle with these, because you can easily over-tighten and break the stud off the electric solenoid. 

(3406E fuel filter base photo_in paint program 2.jpg)

(3406E injector.jpg)

3406E fuel filter base photo_in paint program 2.jpg (37KB - 433 downloads)

3406E injector.jpg (52KB - 404 downloads)