Do you mean PO131 and PO151? I know codes that are P1131 and P1151.
PO131=O2 sensor Circuit Low Volts (Bank 1 Sensor 1)
PO151=02 sensor Circuit Low Volts (Bank 2 Sensor 1)
Usually means the O2 is on its way out on both sides. But you may be able to take the O2's out on each side and take a wire brush to eht tip of them to clean them up. Re-install them and see if the codes come back. If they do, then it is time for new ones. The Ford tech manuals calls for replacement of O2's after 65k miles. After 65k, you are waiting for them to go bad. But try the wire brush on them, also when you take them out, make sure the tips are in good order, I have seen that code when the tip feel to pieces like a broken light bulb, the inside tips are made of porcelein or ceramic material.
2015 Race Red Performance Package GT 5.0 (435hp) stock
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