Replaced O2 sensor. Problem came back less than a few months later. Fortunately, always went away on its own in a few days to a week or two. But now the check engine light has been on for two months. Cant afford the thousands of dollars to replace a dealer (stealer) only part. Yes I live in Commifornia where you can't replace a catalytic converter yourself. Toyota has really gone down hill in the last couple of decades. Makes me wanna start buying domestic again. "The Devil you know..."