I have a 2004 Sti, it makes a strange noise when decelerate at 2-3k rpm from 4-3 and 3-2. I checked it already and most likely the problem is from the area around the turbo heat shield. Anybody havin a familiar case like this? Will it be harmful for the future?

 

Do you have any idea how hard it is to diagnose a noise through text? What you are probably hearing is the deceleration noise. All subarus make it in one way or another. Typically if you have a noise that will cause you a problem. You won't even have to ask if it will cause problems you'll know. Have fun.

 

Well, the noise is more like rattling. Somehow, there's metal vs metal noise. I don't feel any power loss or anything but it's just annoying.

 

It's sounds like the same problem I had. It was a metallic rattling sound between 2-3K rpm. It was related to welds coming loose on the heat shield. I took it to GST Motorsports in Hayward, formerly associated with Gruppe-S, and it was one hour labor to re-weld it and stop the problem. Have them check it out. See gstmotorsports.com.

 

do you have an aftermarket downpipe? Cuz a friend of mine bought one and installed it, and since it was a cheap one, was rattling against the firewall during deceleration...