2004 6.0 Thump
 

I have a 2004 F350 that has started making a strange noise. It sounds like a hollow thump coming out of the intake. It is consistent with engine RPM. It doesn't seem to affect the engine power, but I haven't tried to pull a heavy load. It does have a little lag between depressing accelerator and actually accelerating. I haven't checked for codes yet. Can anyone point me in the right direction?
Tks

There is a guy that drives around town that has the same thing, look in the 6.0 area would be better than in here, think I saw a YouTube video and they said it was a lifter issue.