Rattling sound from underneath the car?

[SBC RACING]

I got home from class today and parked the car, i reved the car a tiny bit because i thought i heard a sound and i noticed that when i rev it a bit then let off i hear a faint rattling sound comming from underneath the car as the rev comes down. I popped the hood and the sound was not comming from that area. I am confused about what it could possibly be. What do you guys think?


Please help me out thanks.

 

[SBC RACING]

please help

please help

 

[WhiteDevil]

Do you have an aftermarket mid-pipe, like an O/R X or H? If so it could be the air pump tube that conects to your pipe. Mine rattled for a litle bit until i secured it, since the stock H-pipe has a bolt holt for it bit most aftermarket ones done.

 

[EpiKk3]

Is it something in your exhaust, or even your exhaust perhaps loose?

 

[SBC RACING]

reply

I have fms shorty headers, stock h-pipe, and bassani catback. The rattle only happens when the car is in neutral and when the rev is comming down. Could it be something serious? (the check engine light is not on and the car drives fine so i dont think its the motor) How about the transmission? (Overall the car drives fine) What do you guys think?

 

[donjohn]

well, i've got the american thunder flows so i'll describe mine which was totally cosmetic and non-internal.

first, where the pipe goes over the axel, the ubolt was loose on the driver's side and the bend was rattling against the frame.. tightened that but still had a noise. the second noise was from the pass. side and was the tailpipe rattling against a metal piece that hangs off the gas tank, so i loosened the mid-to-tailpipe connection and moved it outta the way a bit.

this was all at the same rpm u describe, so i'd first check if ur catback was close to hitting anything also if it's tight or not

 

[SN95StangMan]

My brother's old car had that. It was his tail pipes rattling against a broken exhaust hanger.

 

[Mrgreen94gt]

My catback is rattling horribly right now, mainly when I make left turns. Been doing it ever since I got my x-pipe put on. I've just been too lazy to get under there and do anything about it.

Exhaust rattling has to be one of the most embarrassing things you can have going on. The looks people give you in parking lots makes you wanna disappear from behind the wheel.

 

[95CobraMike]

could be your flanges that bring your exhaust together. my flanges between my h-pipe and flowmasters were rubbing on the underside of my car, right near the driver's side seat. i just had to loosen the bolts and turn the flanges so they no longer rubbed.

 

[donjohn]

Exhaust rattling has to be one of the most embarrassing things you can have going on. The looks people give you in parking lots makes you wanna disappear from behind the wheel.

i dunno about the worst,
1) my clutch makes a sound like when u lay on an old matress and all the springs like creak, every time i compress the pedal

2) at low speeds when i turn the petal one of the loudest, worst creaking sounds u've ever heard

all fixable for 100+$, but who's got money sittin around... i did just buy like 500$ worth of books

 

[Badder Adder]

I had the same problem with my Magnaflow H-pipe. The sound in my case was the result of a chunk of the ceramic guts of the catalytic converter that had broken loose and was rolling around. That is why when you let off the gas you hear the noise... the pressure of the exhaust holds it in place untill you let off the gas, then the pressure drops dramatically and the chunk flies around in the turbulence..

 

[94TURBO5 O]

Your converter is prob cracked on the inside and it's a chunk rattling around in there. Listen closely to each converter while someone revs it for you. You can also just crawl under there (when it's cold) and tap around on each of them and see if you can discover which one it is.

 

[Mrgreen94gt]

i dunno about the worst,


all fixable for 100+$, but who's got money sittin around... i did just buy like 500$ worth of books

I only spent about $200 last time! That was for about 8 books.

 

[mystang94gt]

Im with Bad Adder and 94SC50 more than likely a bad cat. Got one myself right now and you can only hear it sometimes. Especially crawling through parking lots at like 1200 rpms. Sounds horrible. Although I hope to be rid of it soon cause I got a new Magnaflow cat on the way.