alright i have an '06 LS coupe with a 5-speed (totally stock). it seems like every time i get into 3rd and slowly accelerate the muffler sounds like its a flowmaster, then when i get into fourth it goes away. It really only happens when i'm at about 4 grand rpm shifting into third and letting it coast a little after the shift into 3rd then accelerating it normally but the rpm never drops below 2500. why is it making this noise with no aftermarket intake or exhaust, is it just me or is there something wrong guys?

 

i dont think thats a problem..

i used to live in san ramon..