'97 GSR, New b18c1 installed 1.5 years ago, Custom Exhaust (Magnaflow resonator and Muffler), AEM SRI, DC Sports JDM Type-R 4-1 Header.
NO Heat shields are installed.

For the past 1.5 months, every now and again... at 1800 RPM an EXTREMELY Loud rattle is comming from the car (sounds like large pieces of metal smacking into one-another)... wether i'm in-gear or not... I can not tell if it's from under the car or the lower part of the engine bay.

Whenever it does it while i'm at home or at the muffler shop... i raise the car and the sound magically stops! ALL THE TIME!

The car runs perfectly, all the time... i've got Oil Temp and Pressure and Vacuume gauges, they say everything is perfectly fine. My temp gauge is fine.

I tapped everything under the car trying to figure out what it is... nothing... i tightend (most didnt turn) everything i could... I thought it was the Springs and bolts holding the Header to the Exhaust pipe... replaced them with stiffer springs and checked the gasket, perfectly fine.

ideas? i can't figure this out!
Thanks all!

 

Have you considered the brake dust shields?

 

i just checked them... their not rattling... it dosent sound like a heatshiled anyway (i remember the header heatshead rattle i had) it's more of a heavy metal to metal contact ... if that makes any sence

 

my O2 sensor came loose the other day...give it a wiggle

 

Also check your A-pipe bracket to block bolts, mine came loose and made a major rattle.

 

Does it happen standing still too? Or does it happen only when driving?