Rep Power: 257

when i come to a stop i hear a rattling hissing noise that slowly dissapates after a complete stop could my exhaust be the problem the noise is from under the car.

 
Rep Power: 231

rattling hissing? what kind of exhaust are you running? and is it a full catback?

the only rattle thats 'normal' is the one where the flanges of two pipes connect right below a heatshield under the passenger side. and even that rattle should only come when its snowing or raining out and the water gets in there.

 
Rep Power: 257

i have fuul header back 2.5 tsudo N1 ok it was raining when it started to rattle but i modified the heat shield so the flange won't hit it. today i drove it and it didn't rattle but it still makes the hissing sound when i installed the system it did have a miner leak im guessing it got worse with time also i didn't use the spring bolts because they were rusted badly . maybe i should cut the flanges and weld everything together.

 
Rep Power: 812

prolly leaking around a gasket

 
Rep Power: 231

the gaskets are cheap and easy to get. i would try to replace a cheap gasket that would only take a few minutes before trying to weld it together.

 
Rep Power: 257

today i got under the car and tightened everything up the down pipe was really loose at the donut gasket it seemd to do the trick but im going to ordr a OBX twin loop to replace the N1 im tired of it so im going to cit the flanges and weld it together also to gain some clearance.