These codes have been my nemesis for awhile. They come and go randomly. The 02 sensors check out good. I was talking to my mechanic who does stuff for me that I am too old to do LOL, he said you may have a clogged injector. I ran Techron and the light went out, but came back on the following fill up. I decided to try a tank of E85 and it initially threw a lean code both banks, but that quickly resolved itself and all the lights went out for like a month now. Anecdotally I can say that E85 is a hell of a fuel system cleaner. LOL