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It seems to be a generic error and is not only for my car.
If the issue is on both banks, check the maf sensor (air flow meter) out puts. If the maf is reading wrong then you will get a lean condition on both banks. That is where I would go next.
I solved these errors replacing the MAF, but it may be a lot of things from vacuum leaks to fuel filter, air filter, lambda sondes and injectors.