I noticed today when I floored it to get on the interstate that at about 4000 rpms it sounded like the valves was rattling. The car runs strong and has low miles. You dont hear anything in any other part of the rpm range exept right before it is going to switch gears when getting down on it. Has complete tune up done recently along with oil change. Could it be that I need a valve job with such a young engine? If I did need a valve job would you only hear it at high rpms or all across the rpm range. I was also wondering do you think it would be worth it to go to synthetic oil. Appreciate your input..