Strange rattling noise....

Ok...I recently put my headers and catback exhaust on my lude....a few weeks later I am noticing this really wierd sounding buzzing sound at around 2.5-3k rpm.. This sound ONLY happens when the car is accelerating. I could not make the car generate the sound while in neutral....parked or moving.

Help?

It could be your cat's rattling. Mines do it sometimes.

While under the car double checking all heat sheilds, connections, etc....I noticed that the horshoe looking bracket that braces the header downpipe was broken.

Got that spot welded and it cleared up the rattle.