I've gotten this code twice now. It seems to be intermittent. The first time was after driving the car harder than usual
. It popped up the next morning when I turned it on. I cleared the code and it didn't come back till maybe 6 months later (yesterday) after I got some gas from a sunoco that I've never gotten gas from before and I was also driving it a little hard through some hills and twisties. Cleared the code again and so far hasn't returned. My car is 100% stock with 84k miles. The only two things that I see in common between both times was hard driving and hot weather.