okay, so i have a 2000 grand prix gt, no mods on the engine everything stock, out of no where my car has been making a wierd noise after acelerating for about 2 weeks now, no check engine light or anything but when ever i aclerate to about 25+ and stop touching the gas it sounds like a basball card in a bicycle tire noise if you know what im saying, i reved it parked and it makes a noise aswell ans it seems to be coming from the exhaust end, any idea? or should i just bring it to my local mechanic and see it they can diagnoise the problem?