Been getting a very intermittent rattle when idle, that seems to be getting more frequent or noticible lately, but it has also been between -20*f and 5* for the past few days, not sure if that makes any difference. Idle rail ksi is about 4.1-4.3, with some spikes randomly to 5.5ksi or so, then back down to 4.1-4.3. I also uninstalled my MCC tune and went back to the box tune (6.8.39 i believe), and still have the same rattle. If I high idle, it disappears. Also, still has good performance and havent noticed any other issues besides the sound. Its been suggested that I may have an injector going out and should take it in for an injector kill test. Any other ideas or what this may be? I currently have about 46,xxx miles on it, been deleted since 5,000 roughly, running 50/50 fuel with howes if that makes a difference. I will try to attach a couple of videos of the sound from photobucket.