It was a 1991 Camry 4 cylinder. I may have said MAF. It could have been anything that had to do with the air flow. It was over 5 years ago and all I remember about it was it was high up on the list of things to replace for the problems I though the car was having. That was from a web site like Autozone. I took it to a dealer because the sensor was around $ 500 to $
600.As I mentioned I later found the dealership was not too well thought of for repair work. Looks like if it was simple to check , the mechanic should have done that in the nearly 3 weeks he was looking at it. Also he should have done some other things you mentioned, but must not have done those either. I think he was just a parts changer and did not do any real tests.