Hey Alpine...I just got back from the Nissan dealer and they said that yes their is a knock sensor code but all systems passed and they cleared the code and when I drove it home the same shit happened..loss of power and ran real shitty. In your one post you said sensors wear out...since it started doing it again,do you think the knock sensor is "going bad"? Because I will go back and insist they replace it. Let me know what you think.