[1JEWLDSSRS]

Check your tunnel brace at the front of your system, can't really tell, but it looks kinda close to touching the pipes at the front of the catback, maybe when the engine torques ove while you are driving it the pipes are touching it? And maybe when you are banging on it, it is touching? Just a thought. Sometimes when you have a 3 inch catback the pipes don't clear the brace very much, that's why I had to install a BMR brace on mine, or you could install some washers between the floor and the brace for clearance.