I have been experiencing this crackle/rattle noise when my car is just sitting in idle and maybe sometimes when driving at low speeds. At acceleration speeds (and driving normally on the street at 45+ mph) the sound goes away. This noise appears to be coming from the top right when sitting in the driver's seat. However, I can't find the noise when the hood is open since there is a lot of other noises overpowering it, so it's mostly more noticeable inside the car itself (I will get back to this in a bit).

I first started noticing this noise after installing new intakes (JWT Popchargers). The noise was not there at first but after 3 weeks the noise started happening. I tried to check my brackets, bolts, and clamps and all of them are tight. None of the parts are in contact with anything in the engine bay. Going back to the noise, it was much easier to find it (inside the engine bay) when it first started happening. The source sounded like in the bottom left of the engine cover, but after a few days, the noise stop and over the weeks it came back slowly but quieter.

In the video attached, you can hear the rattle but it's very faint. It's much louder in person, so I tried enhancing the audio a little to try to bring it out. Does anyone have any idea whats producing this sound?

 

Sounds kinda like a rod knock or internal engine noise, can you get under it to take a listen?

 

I have not gone under it to take a listen. Are there common spots I should listen for when I do get under it?

 

Oil pan area if you’re underneath, but even down at the back of the front wheel area, with the car on the ground may produce a noise, there are some obvious normal noises under the hood when running, but many of those are gone below the car, which is where you would hear a bottom-end noise from.
How does the oil look?

 

I changed my oil around 1500 miles ago. I use Royal Purple HPS 10w-30. I check my levels every end of the week. The oil level does not burn as much (I have a 2008 HR model)

 

Just saw your post. I had a rattle coming from the drivers front when driving and at idle sometimes. It drove me crazy. I finally discovered that it was inside the headlight assembly. I heated the headlight in my oven to take it apart and saw that some of the plastic pieces inside were loose and rattling. I glued them together and resealed the headlight assembly and now no rattle.