XpEdItIoUs

iTrader: (44)

Today when i started my car i noticed a rattle coming from under my car it kinda sounds like something is loose but it goes away when i drive or maybe cant hear it but it it seems to go away for a while and comes back should i worry.

NBM2k2SS

iTrader: (2)

Its probably your 02 sensors rattling, lay under the car and listen...

Another_User

I have found an assortment of spots the exhaust can rattle.
1) O2 sensors loose (rare)
2) Y-pipe hitting under car
3) aftermarket exhaust hanger hitting heat shield on gas tank
4) vibration causing metal exhaust hanger to move back and forth through the rubber exhaust hangers (weird one, but this is what has been happening on mine)
5) exhaust resonance vibrating heat shield on gas tank

I am sure there are plenty of other places rattles could come from, but those are my favorites.

LS1LUNATIC

iTrader: (3)

its the heatshield most likely. I know of 4 Fbodies with that problem.

RPM WS6

iTrader: (3)

Honestly, there are about 100 spots that could be rattling to fit your description, some of them not even exhaust related (I found one of my rattles to be a fuel line vibrating aganist a heat sheild). You'd need to at least pinpoint the general area (front, back, middle, driver's, passenger's, etc.) before going any further.....

PureWS6

heat shield almost always

XpEdItIoUs

iTrader: (44)

It's coming from the front of the car near my transmission.

tcarswell

Had the same problem it was my heat shield

SSactionLs1

youd probably have to have it running on a lift..

RPM WS6

iTrader: (3)

Might be an O2 sensor then. Mine were doing this on the '00 car (the rear ones). Not really sure what causes it, they weren't lose, but something inside them just rattled. I tried the trick of taping up the sleeve rings with some HVAC tape but that only helped a little. Once I pulled 'em off the sound went away entirely.

XpEdItIoUs

iTrader: (44)

I think it might be my 02 sensor because a while back my rear 02 sensor on the drivers side came loose. I will problably take both the rears off today.

hourang

iTrader: (6)

my clutch rattles some when i have it disengaged, i think its the slave that causes this.

side note: dude you need some longtubes!!

XpEdItIoUs

iTrader: (44)

Yes i do

XpEdItIoUs

iTrader: (44)

I was under my car today and the rattle isn't coming from my heat shields i cant figure out where its coming from. It sounds like someone kicking a can with a marble inside of it.

XpEdItIoUs

iTrader: (44)

Could it be my cats going bad.

RPM WS6

iTrader: (3)

Sounds similar to how the O2 sensor rattle did on my WS6.

Try this: once the exhaust is cool to the touch, trying getting under the car and banging on the I-pipe and Y-pipe with your hand. Do you hear the same sound when doing this as when the car is idling? That's how mine was, and it was the rear O2s.....

RPM WS6

iTrader: (3)

Possibile, try banging on the cats (not too hard) with a rubber mallet and see if anything is loose inside them.....

XpEdItIoUs

iTrader: (44)

well im going to get duals soon but first i will try removing my o2 since they where deleted with my tune if that dosnt work than im guessing its my cats.

XpEdItIoUs

iTrader: (44)

I dont know if this matters but there is ash coming out of the exhaust not alot but some.

RPM WS6

iTrader: (3)

Ash-like substance could certainly be the cats breaking apart.

Again, try hitting them with a mallet and see if anything inside is loose/bouncing around. Should be fairly easy to tell.......