idk if it has anyhitng to do with my exhuast but when i start moving backward (in reverse) there is a weird clanking noise anywhere between 1500-300, everyhting feels right with the tranny so im guessing its not that, im thinking the heat sheild above the cat could be shaking casue have a new cat but thats just a wild guess... its not hurting performance so im not too concerened but any ideas??

 

Probably just the heat sheild, nothing to worry about.

 

Jack up the car put some stands under it. crawl under there with a light. have someone move the gear shifter into reverse and see what is happening....

just a thought.