So, I threw this code and took my truck to the dealer. He told me my K & N filter could be the culprit and that if I didnt go back to an OEM filter it could void my warranty. P042E is for a stuck EGR valve. Before I bought the new filter, I ask the dealer where I purchased the truck new if a filter change would affect my warranty and was told no. I no longer go to where I purchased my truck because their certified techs quit and they cant do warranty work. Are they correct in saying that 1. my airfilter could be causing the sooting problem and 2. other than OEM will viod the warranty?