So my 04 rx8 just started making some strange noises as I was driving it yesterday. Whenever I go over 40mph I can start hearing a whacking or knocking sounds coming from the front passenger side of my car. I pull over and pop the hood and I believe the sound is coming from the engine area. However it quickly subsides. The sound is very noticeable and only comes when I'm going 40mph+ no matter what gear and rpm I'm at. It takes a second for it to start and also for it to go away once I go under the 40mph. Car seems fine in power has good coolant levels, oil is full and my obd scanner doesn't show any relevant fault codes to this specific issue. Then a side note I'm not sure if this is normal but when I start up my car for a few minutes it has a kind of high pitched cricket like sound that then goes away after a while.

​​​

 

Sound seems to be coming from a small metal actuator located near the engine under the intake manifold. My best guess is that it controlls air intake. Actuator is obviosly old it still works but it vibrates making sounds. When I touch the peice the sound automaticaly goes away either I just need to clean it or replace it. Anyone know what this peice is called if I need to order a new one? Car is still making the cricket sound makes me think of a vacuum leak ill test that soon with a smoke test.
Thanks,

Peep the youtube links for a better look

 

I forget which actuator (VDI or SSV) that is but I think the shaft wears and develops play and that's the chirping/tapping sound you hear at idle.

The other sound that you're hearing at speed is probably a plastic part flapping in the wind. Check your undertray and fender liners.

Edit: looks like that's the SSV actuator.
https://www.rx8club.com/series-i-tro...8/#post3098312

 

Check your undertray and fender liners.