A/F/R gauge for tuning
I’ll simply just add this for the benefit of the OP, as to not get dragged into the mess of much of what has been put out here so far. My advice would be to find a reliable A/F or dual band O2 sensor and gauge to install and do some research into the ACTUAL way O2 and A/F sensors REALLY work, to gain an understanding and then find someone locally who can help hands on who is familiar with turning with them. A/F gauge is not the be all end all of engine tuning but can give you a window into what is going on during a run or cruising etc.