My gta's have a rattle when i take off from a start or under light acceleration. When i crawl under the car i can hit the drivers side muffler or the mid pipe and i get a rattle. It does not seem to be the muffler i think its the rubber hanger brackets. you guys have any ideas?

 

The rear hanger on the drivers side of a GTA muffler is sometimes too long and it can hit the metal bumper. If it is hitting you can try to reposition the muffler or cut a 1/4' off the hanger.

 

80% of axleback rattles are the clamps.

 

Found it. It was the hanger the hard to get to bolt was about 3 turns loose no more noise but its a vert so plenty more noises left.