I have a 2004 Dbl cab stock with 8500 miles on it and I noticed the other day while I was sitting in my driveway that when I revved the engine to about 2500-3000 rpm there was a slight clunk in the engine bay. Tried it again and it didn't do it, so I drove it around a little parked it and revved the engine again and it did it. But the thing is it only clunks once or twice and the stops and sometimes when you try to reproduce the noise it wont clunk. It almost sounds like something is lining up and the clunking into place but I don't know what it could be. I want to bring it back to the Dealer but with the problem not happening all the time I can imagine what they are going to say. Any ways any ideas would be appreciated.