Search has never worked for 3 letters and I'm working on a cure!

Your still shooting for 128.

In theory a stoichiometric mixture has just enough air to completely burn the available fuel. No fuel left, no air left.

Contrary to most everything on Internet a narrow band O2 sensor does not adjust to 14.7 AFR and a Cat Converter does not work best at 14.7 AFR. Narrow band 02 Sensor adjusts to Stoich and Cat Converter works best at Stoich. Just happens that when these vehicles came out gasoline with no E or Oxygen enhancers was Stoich at 14.7 AFR

Now most fuel everywhere is E10. A safe AFR for starting point of a tune is 14.1, there's still some controversy in my eyes as Internet has estimates from 13.8 to 14.3. Testing my fuel here showed 13.9