Alright, well yesterday just before I got to work, I was sitting in traffic and noticed a weird noise from under my hood every so often, maybe like 10 seconds apart or more. Sounds kind of like a clunking, or a knocking. Anyways, after work I get home and when the car idles it happens about every 5 or 6 seconds, just a clunking or knocking sound again. For some reason, another sound it makes is that it sounds like you try to start the car once its already running, but not so whinish/high pitched. The engine has had a bottle of nitrous go through it if that helps at all, as well a cam was installed about a year ago. Could a rocker have come loose or something? Any help would be great, thanks.