I have a buzzing noise in the trunk lid. Could it be the plastic? Motordyne CBE
 

I have a buzzing noise in the trunk lid. Could it be the plastic?

Exhaust : Motordyne CBE

It could be all sorts of things. Get someone to ride along and see if they can locate the source while you concentrate on driving.

There's a common issue from what I remember:
https://www.youtube.com/watch?v=YxXKbfkMWq8 may show it

Dude Ive had my trunk/hatch apart for about a year now, and still havent found the source of the buzzing noise.

Please post your results if you find it!

I had it in mine and it turned out to be the hatch gear motor box ..... took it out opened it up and put some heavier grease on the plastic gears .... before you could shake it and it would rattle after thicker grease no more rattle.... I never thought that little thing would cause so much noise and rattle .. but it stopped every bit of it

Same here.

Yep did that already..no change for me. Still buzzing, sounds like an electrical short!

I have also:
1. Removed and re sealed the back glass.
2. Removed the rear hatch weight.
3. Removed all the plastic in the trunk and spare, foam, tools etc..
4. Removed the third brake light high mount assy completely.
5. Replaced the rear hatch seal.
6. Replaced the two spring bumpers with upgraded part #.
7. Re-set the rear latch position, to tighten up the hatch to body.
8. Removed all the wiring harnesses from the rear defrost and third high mount brake light from its mounting on the rear hatch.

The noise stopped when the defrost harness on the driver side of the hatch was removed and rolled up.

So at this point I am thinking drivers side rear defrost wiring harness.