Have some sputtering in the little monster. Originally got a code for coil. Swapped coils and light issue solved but not sputter. Ended up changing all four coils, still sputtering. Replace all four plugs, which BTW looked like they were burning fine. Ran a can of fuel cleaner through, still no change. I have 48K on the car with zero issues until now. I don't pamper the car as I have a collection of rods some with some significant HP so I doubt carbon but ???? I can't see any leaks or gaps in the air intake system.
Anyone out there who had the same and solved it.

 

Sputtering as in, difficult to start? Or sputtering while driving?

 

sputtering while driving, sorry I didn't mention that

 

Otherwise it doesn't idle rough? Or hesitate to start?

 

My knee jerk response was HPFP, carbon build up and fouled fuel injectors. However, the sputtering would be pretty consistent, and not just while moving.

 

seems to idle fine just when accelerating and mostly on the lower end.

 

I am having the same issue with sputtering. It only happens if I accelerate quickly at higher speeds, not at all when going slower. Recently rebuilt the head with all new valves (damaged when timing chain went). Top end is all new but I haven't replaced coils or spark plugs yet. Have you resolved your issue?