Welcome to the forum. Your first project needs to be studying emssions devices, and what they do. Most people including me do not like working on something they don't understand. But since you need to keep all the emssions on your truck, I would learn as much as I could on everything that is on the engine. None of that stuff will hurt the performance of the engine if it's working correctly.
Here's a good site that list the abbreviations found on your emissions diagram, and has some explanations of what they do.
Dictionary of Automotive Terms A-Z
