Hello titan xd forum, im new to the website. I recently bought a 2016 nissan titan xd from my uncle. He had the after treatment delete and ppei tune. I put everything back to stock and drove the truck over 800 miles. I still have 4 incomplete monitors how ever no Check engine light. Has anyone converted there truck back to stock and had hard time with smog. Please help, last choice will be take to dealership.