Check engine light was on and would flash at times and would bog down and shake vigorously , changed plugs and they were fried beyond belief ( surprised it was starting). Still no change, so changed all but one c.o.p. because I misplaced the last one, still no change. Checked fuel pressure and it was only at 15 and would drop to 12 lbs. Under slight excell, changed fuel pump ( inside tank) got a good reading on tester, but would still shutter going up hills, drove up a mountain and pulled over to check cats, lower cat on drivers side was glowing, so I eliminated both lower cats , knocked out the top cats ran pipes and put on a glass pack, sounds phenomenal except a still feel a shutter/mis, I'll be changing the fuel filter and replacing the last c.o.p. just wondering if this doesn't get the bug out what else can it possibly be? Truck runs much better with what was done

Thanks ,Pam