Chevrolet: 2000 Camaro SS, 2000 camaro ss, chevrolet dealership

Question
QUESTION: Rattling noises (mostly under hard acceleration)
Went to many garages (including Chevrolet dealership) and no one seem to be able to find what's causing the noise.  I love this car, I hate the rattling sound under acceleration.  Can you help?
ANSWER: You're going to have to help me out here. LS1s are not prone to rattles under acceleration. Do you have any modifications done to the car? Where is the rattle coming from? Front of the car? Under the car? Rear?

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QUESTION: Only a K&N air intake and a U-haul hitch.  The car is stock.  Rattle sounds from under the car and happens about 80% of the time.  It sounds like something is loose but I can't find anything.  I can make it rattle when I drive at 2000 RPM in 5th gear and I floor it. (I don't drive like that but that's what I do to show the mechanics the sounds that it makes) I also hear is when I accelerate and the tach reaches 5000 RPM or so all the way up to the red line.  It doesn't happen at mid RPM nor when I just cruse.  I recently had a new Cat. Conv. installed, rebuilt transmission and diff.  The rattle was there before and is still there after.  Does this info. help? Thank you.

Answer
Are you sure its a rattle and not a vibration?

If it was a vibration I would suggest the driveshaft since there is a technical service bulletin on that.

Otherwise if its a rattle it would either be an exhaust shield or broken tranny mount.

Best thing to do is put the car on a hoist and give everything a good shake.