Really diving into details there @Tester and missing the big picture.
They are listed as oxygen sensors on parts websites, in the Bentley manual, and everywhere I read about the two oxygen sensors for my car. Perhaps mechanics cll my oxygen sensors air/fuel ratio sensors, I do not know. But none of the facts change becuase of what they are called.
@sgtrock21 The EPA estimate is always on the conservative side and that my nine year old car with 77,000 miles on it gets nowhere near the EPA estimate is the problem. Of course I have no idea how the car was driven before I bought it at 70,000 miles. The slighty melted plastic of the intake manifold indicates it was driven badly. My whole point is that the car doesn’t get anywhere near the mileage it should and jumps all over the map so something is obviously wrong.
The compression test is the best advice so far and will be done tomorrow.