I have a 2001 4x4 SRW 7.3L PSD and have had a heavy shaken-not-stirred type of vibration while cold. The truck shakes REALLY bad until things have all warmed up. After that the vibration just ceases. It doesn't really go away gradually, just suddenly everything goes smooth again. I also noticed that if I really get on the gas early on the vibration will cease. What makes me think it's an injector issue is the fact I had the harness come loose from under the cover a few months back and it took out that whole bank of pistons. The vibration was the same as I'm feeling now while cool with the exception of severity. It was WAY worse with ALL the driver's side pistons not firing. My thought is that MAYBE, it has nothing to do with actually being cool, but there could be air in the line and the lovely 8 piston could be getting nothing until the foam and air are worked out of the line. Now this has several ramifications if true, but I was wondering if that indeed could be the issue and if anyone else has had that problem.