Should we flash the stock firmware back to the ECU to diagnose the car? I feel like running all the mods and customizations could either cloud the diagnosis/what we need to replace to fix the issues we're having. multiple cylinder misfires--1,2 and 3. Another code is the pre-cat lambda probe....the fuel trim is reading at 50 at it's highest, sometimes in the 30s......ones stuck at 25.....