Originally Posted by Jhill

Eugene does it through o2 feedback as does some GM vehicles. When at GM though I had vehicles that wouldn’t re learn because drivers would not drive the vehicle to meet the requirements to re learn (essentially would not do a long enough drive after switching back) and then the vehicle would get stuck and run rich until you forced a reset in the ecu. So I went with Sebs tune with a sensor but maybe ecutek can do a better job with just o2 than GM algorithm.