I finally have another day to work on my truck. I replaced the glow plugs because the PO said they used Autolights. Well, they were Delcos, no matter...they came out like butter and they're all swapped with ZD9 now. One thing that really concerns me is that one of the glow plugs was covered in gritty, muddy looking diesel. The grit had some teeny tiny metallic dust flakes (almost looks like the flakes are coming off of the metalic glow plug tip) but overall, the grit looked like rusty mud. It was the second cylinder closest to the firewall on the passenger side. My return lines have been leaking like crazy and I am replacing them at the same time. They leaked so bad that glow plug valleys were pooling up with diesel. I noticed that in this particular glow plug valley, there was no pool, it was wet and leaking from the return cap above... I very much doubt the fuel would have been able to leak past the glow plug carrying along the grit that had collected in the valley, however, that's my only thought. I am nervous to hear what you all think.