Ok, so let's start here:

2008 Suburban LT2 5.3L with 125,XXX on it. Initially had an issue with a "faulty" valve cover that would fowl plug #1. This is described in a TSB. Oddly enough I had a Chrysler Warranty at the time and when I tried to have them cover it but it was declined because of the TSB and the Chrysler warranty stated that anything that was a "known" manufacturer defect would not be covered. The Chevrolet dealership stated they could not take of me as the truck was out of warranty.

The problem now is that I have replaced plug #1, not replaced the valve cover as the repair cost is high at the dealership and I do not have time to do it on my own at the moment. Currently the truck is throwing P0172 and P0175 codes, Bank 1 and Bank 2 Rich. I have cleaned the O2 sensor(Mac scan tool verified sensors were functioning fine), air filter(not replaced), tried using premium fuel, and a fuel injector cleaner. One thing that I did notice is that the purge valve is constantly on attempting to create vacuum.

Does anyone have any recommendations as to where to proceed from here?