First off, the tune I'll be talking about is a basic 5.3/4l60e LS Swap tune I'm using in my 73 C10. Now the issue. when I come to a hard stop, slam on the brakes, I get a MIL light. I've checked the codes and it shows both O2 sensors not functioning. I get both sensor codes at the same time. I don't get the MIL light during normal driving. I've checked the live data and it shows that both O2 sensors are putting out a reading/fluctuating. I'm only running the front two sensors and they are for a 2002 Silverado with the 5.3. Any thoughts on what may be causing the MIL light to come on?