Jeep SRT8 P0171 and P0174 Lean Codes: Diagnosis After Major Modifications

I'm experiencing persistent lean engine codes P0171 and P0174 on my Jeep SRT8. The issue started after I reverted to a stock cat-back exhaust system. I drove the vehicle for several weeks to allow the ECU to reset, but the codes persisted. I then switched back to a free-flowing exhaust setup in hopes of resolving the issue—no improvement was seen. Fuel trim readings show Long Term Fuel Trims around 30% and 25%, with oxygen sensor readings fluctuating significantly. I've ruled out common causes: no exhaust leaks, no vacuum leaks, and I've already emptied the catch can. The 6.1L Hemi uses speed density air metering instead of a MAF sensor, which makes diagnostics more complex. No one seems to have a clear path forward. The vehicle is currently scheduled for a visit to my dealer—also my ECU tuner—on Monday to investigate further. Modifications include: - AFe Cold Air Intake - 180° Thermostat - Billet Tech Catch Can - 90mm Arrington Billet Throttle Body - Inertia Ported Intake Manifold (modified) - BWoody Thermalnator Intake Gaskets/Spacers - Superior/GSM Ported and Polished Heads (modified) - Comp XFI 2 TDC Cam - SRT4 Stage 1 (55#) Fuel Injectors - Stainless Works 1.75" Headers with Random Tech Catalytic Converters - Borla "S" Cat-Back - DiabloSport Trinity with Base Tune The truck previously ran reliably on the base tune for over a year, achieving sub-11-second times—now it's throwing errors consistently. Any insights or troubleshooting steps would be greatly appreciated.