[BNtune]

I'm sure the air filter has been changed. The air inlet to the filter has not in some way gotten blocked. Sounds like it's choking out.
Once it starts showing a Lean running eng. it will than run rich. Fuel psi ok? One or more injector leaking?A bad injector sould cause a misfire, that you don't show. O2 a good ideal and they don't always show a code. CTS not with in range. MAP will cause a rough and rich running Eng. Now what is causing the lean code? Fuel psi.,Fuel filter.