I have been having an issue with my 2004 6.0L making an odd revving sound when returning to idle. This issue us accompanied by a surging/loss of power. the IPR during these times is in the mid-30% range while the ICP is around 600-800psi. I have my suspicions as to the issue, but would like to hear your opinions. I have a video of this happening linked below. around 40 seconds in I roll off the throttle and the the issue starts. I roll back in with some surging and then roll back out to the same idle issue. This will happen warm or cold, but lasts less than a minute. After that it seems fine again. I replace the fuel filters every other oil change. The filters were replaced this weekend.