i have been getting a dtrange almost rattle like sound when in 3rd-4th low revs and put footdown slightly (around 2000rpm) in my 01WRX - not knowing to much have been wondering it something in the turbo is slightly loose(seems to come from behind the steering wheel) anyideas?? the only other i can think of is a slight air leak but doesn't sound like it,

Thanks,

 

Could be the heat shield.