I've been wrestling with this for a good while now and swapped out any part I could think of that gives this symptom. I've had my 03 f250 6.0 to 2 different diesel shops and 1 dealer with nobody able to figure it out. I gave up for a while and just drove the truck but it haunts me. I can feel it and see it in the idle. I mostly notice it when I get off the freeway and sit at a red light. The RPM will fluctuate between 600-670. The ICP pressure does about the same with the RPM. IPR is usually at 24% sometimes 26% but the % doesn't repeat with the occurrence. I swapped the ICP and the connector since most of what I've seen and read point there. There pretty much isn't anything I haven't done other then an HPOP. Other then idle, the truck has no problems. Any obscure ideas or experiences out there would be appreciated. I'll try and link to the videos I took. You can just barely hear it but you can see the readings on my edge monitor. Does it in stock or tune.