I have an 02 Suburban with the 5.3 Liter motor. When it is cold the truck runs rough and throws a p0171 and P0174 (lean condition in both banks). It is also throwing a P0300 (random misfire) code. I just had it to the dealership to have a cat replaced. They replaced it under warranty but then went on to say the intake gaskets were leaking and wanted to charge me 500 to replace them. I have had my T/A's LS1 apart a few times so if that is what it trukly is I could do that myself. I am suspicious though that this problem was not there before and suddenly "appears" after warranty work. Could the dealership do anything that would throw this code? From what I understand this could be caused by an intake leak, an exhaust leak, or a bad fuel filter. Is there anything easy to check or do I just need to get it to somebody to look at? Unfortunately I don't have a mechanic I trust right now. Come on Rutan!