Hello, my car has a P2a00 code. It will not go away. So I should start by saying that my car does have headers on them but the code did not come up till after 2 years of owning it. Thing I did : I changed both of the O2 sensors twice with OEM. I have changed out my exhaust pipe that holds my second cat and flex pipe. I cleaned my mass air flow sensor. Nothing gets ride of them. I have a scan tool OBD2 Bluetooth using Torque. Bank 1 sensor 1 says around 0.3 but when on the high way going around 70mph if I let go the gas it jumps to 0.85-0.9. Bank 1 sensor 2 jumps from .085-.9 to almost 0.0. Looking at the graph it looks like it did hit 0 for a tiny bit then jump to 0.85.
My car has 185000 miles.
My car has an automatic transmission.
If you have only cleaned the Mass air sensor and have replaced all the O2 sensors then the only other possible cause for the P2a00 is the mass air sensor. I recommend replacing the mass air sensor and relearning the fuel control and clearing codes.
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