Hey,
Lemon law that thing! Im a GM dealer and diesel fanatic and im telling you the commercial LL suits are easier to win. The truck is costing you money because you use it for work, right? Well your thread spiked an interst so i asked my friend who is a heavy line Isuzu and Duamax wrench your questions. If you want to ask him yourself look up redline performance diesel in corona california these guys are the R and D company for RBP. They know their Sh@t if you know what i mean. he told me fuel jelling or particulate matter clogging the rails. Hey GM will stand buy the truck if you are still under warranty, get that truck ripped apart or get Gm to give you a new one. I cant believe that a gm dealer says "we dont know" Under franchise agreement with gm we are not allowed to turn anything away if the vehical is under warranty and the problem the owner is describing is possible or could be happening.
JR-
Renick Cadillac