my 15 ram 2500 6.4 about 2 months ago just all the sudden got weak. ive swapped out my k&n filters, a new EGR, the pipe from the EGR had alot of build up two of the holes in the end were almost stopped up so i cleaned it all out, cleaned throttle body. It ran good on the way home that night, felt strong but the next morning back to the same. havent done plugs yet, but will shortly. Nothing has been done to it other than a borla xr-1 and resonator took off at about 20k miles it has 66k now. Im not getting a smell to make me think the cats... Half throttle and full it is still very strong but starting of and re accelerating after slowing down makes it feel like a 4 cyl in that heavy a$$ truck. Any ideas what to check next?