You've gotten my attention Jim. The trouble is when you accidentally punch somebody in the face, saying you're sorry doesn't stop the blood. At least once a week I get someone shamelessly asking me to look at/fix their car because they "don't trust mechanics", and they really have no idea how insulting they are. It's worse when they've made some ham-fisted attempt to fix it themselves and expect me to clean up the mess. Most of the questions you are asking can be answered by reading a service manual. You may want to consider, though, that it is quite a risk to ride in a vehicle that has been "repaired" by an admitted amateur, particularly one without the training to do a basic O2 diagnosis. If you don't want to take your truck to a shop, you need to head down to your local technical college and enroll in some auto-tech classes - the perfect opportunity to ask and learn.