Any help with this is appreciated and I'll try and put as much detail in this as possible.

When driving and when i'm on the accelorator, between 3K and 4k rpms in 2nd and 3rd gear, i'm getting like a sputtering or slight rattling noise. I checked my exhaust, down pipe and up pipe and everything is tight. I even had my local shop check those out on the rack and everything is tight.

Any suggestions or if anyone has any ideas i'm open to it, but my next and last step is the dreaded dealership!!

 

it could be the heat shield on the uppipe. to check just reach in and try to jiggle the uppipe shield
especially sti uppipes the welds break
good luck

 

double post

 

I checked that because I used to have that problem when I put in my Cobb Heat Shield but it's solid.

It's weird, it seems to be loudest after the car has been running for a little bit but it's not affecting the performance at. I have no boost leakage, no exhaust leak and the car runs great.

 

Bump, anyone got any ideas on this one?

 

had a car come in today at work because of a rattling noise at around 4k rpm. i'd say just rack it again and bang on the heat shields to check to see if they make contact with any part of the exhaust. either that or raise it up, throw it in neutral and rev to the rpm that you hear the rattle while someone stands underneath and takes a look. most likely it might be a heat shield that's a little too close to an exhaust pipe.

 

if that doesn't work then that noise might be coming from the trans considering it's in 2nd and 3rd gear, maybe something loose in there?

 

it sounds like wastegate flutter to me. When you are at 3k or so rpms the wastegate will open a little and it will tick or make a rattling noise and it gets very annoying. This happens when you have an aftermarket cat back exhaust or any type of exhaust mods. To fix the problem tighten the wastegate arm a turn or 2 and that should take care of it.