Is the O2 sensor the same as the "air flow" sensor? There are two sensors located on the passenger's side of the air flow valve on a '84 500 SEC. What are these sensors and what should they be connected to. I have both an American and grey market 500 SEC and both these sensors are connected to different components. I suspect that is a query for another post, however, I would like to perform the suggested procedures that have been kindly offered above but I must identify the O2 sensor to procede. William.