So I've had this 2006 acura tl for about a year and a half and ever since I had it it's always made this noise when I start it and when it reaches 1800rpm or 3100rpm (relatively close to those rpms) and I havent got a damn clue what would cause such a god awful noise. It comes from what I can tell from the back of the engine. (The sound in question is the high pitched friction noise that goes on and off). It stops making the noise in park/ idle after being at operating temperature but when driving the sound comes back at 1800rpm for a second and then 3100 rpm as well. It only happens at that specific rpm and stops right after.

 

Anyone?

 

Only thing I can think of that would sound like that would be the insulators for the exhaust (thin metal), but even there I don't know how they could rattle this much. Worth checking maybe.

 

good news is that the sound is most present when you start it and it's cool. you should be able to open the hood and look/hear/feel for where the sound is coming from. I second opinion about being loose thin metal, probably somewhere close to the exhaust/catalytic converter area, could also check exhaust manifold heat shield.

 

Yeah the audio clip I took was with the hood open. It appeared to be coming from the back of the engine bay

 

rear cat heat shield.

 

this would be my guess as well.