Having a bit of a confusing battle tuning a GTO with an LS2. Vehicle only has long tubes but the car sat for many years before being driven again. o2's have been swapped with new ones. Noticing the vehicle going lean and falling into OL - Not Ready. Visual inspection of the o2 wires lead to no fraying or shorting. Even with the stock tune with rear o2's and COT disabled, its doing the same thing.