I had to get the whole exhaust system done 3 months ago ,from catalytic converter to tail pipes. Beautiful ,quiet, perfect, then all of a sudden I start to hear a sound I thought was the base from someone's radio in the distance. It followed me. Got to parking lot at work and realized it was my car. Been back toechanic twice . He says sounds fine. The base noise is driving me crazy. $2000.0P JOB. He says baffle may have broke , it's internal and can't do anything. And that happens with after market mufflers but he doesn't hear anything. Also he had me look at system when up on the lift, I noticed what I think is external rust, after 3 months?. Any ideas.
