Hey guys,
Recently my car has been making this load godawful vibration sounding noise when I first start it up. It happens at a certain RPM range (~2k and also close to ~1k), which you can hear when I am revving it. The weird thing is, after i start driving the car it usually will go away pretty quickly and doesn't return until I let the car sit for a bit (~30 mins) and restart back up.

I tried to figure out where it is coming from, but cant locate it. All I can hear is it coming straight out the end of the driver's side exhaust pipe, like maybe it is inside the muffler or something.

I have stock exhaust /w Berk HFCs.

I have linked an audio file below that I recorded with my phone earlier. Any help is appreciated. Thanks.

Audio file: http://www.kylespearrin.com/misc/Memo.m4a

 

I had an 06' Altima 3.5 that made that sound. Turned out to be the heat shield around the cat. They went in and clamped it down never made that sound again.

 

I have aftermarket HFC's so there isn't a heat shield on them anymore. Maybe another one somewhere else?

 

Anyone else with an idea?

 

check if all of the bolts on the exhaust are tight not loose. or just wear a glove and touch your exhaust to feel which part is vibrating

 

I think that's just the engine warming up... when I first start my g its really loud, but I goes away when it hits 1000 RPM...

 

I have the same problem same sound.

 

The only way to find this kinda rattle is to get your ride on a lift/rack and bang on the system till you find the loose area. Then either tighten or weld it so the noise disappears. I was thinking heat shield too, but HFCs don't have em.
Gary

 

I have the same problem as you, its not all the time but sometimes. Its for a split second, mine is more like a loud chirp but i friend thought it was a vibration sound like you mentioned.

I noticed it after the HFC i installed. I dont think its a loose piece but not sure. Mine is just when you start up the car cold or after a long time ( summer time haven't noticed it). I remember reading somewhere that the car starts a little rich when cold to make it easier on the engine, so might just wierd reaction with the HFC and running rich temporarily at start.

If you find out something else please post it up.

 

I've had my HFC's on for a few months without this issue. The only thing i did recently was lowered the car about 3-4 weeks ago. This just started happening about a week ago.

I dont see how you can say it's the engine? Did you listen to the file?

 

^It doesn't sound like the engine. Get the b!tch in the air and examine the bottom, these cars have many heat shields underneath them.

 

I plugged the drivers side pipe with a rag and can definitely hear it coming from inside the muffler. I'm not sure what's exactly inside a muffler that could be loose. Anyone know what it could be?

 

Sounds like there's something broken inside the muffler and needs to be replaced. Doubt if you still have warranty and it's probably not covered under emissions. I'd go to a muffler shop and see if they can nail down the noise with it on the lift/rack before you spend $$ for a replacement.
Gary

 

Probably the CAT's, mine are currently bad (according to the stealership) and there's a rattling sound around 1,800-2,000 and 2,800-3,400 RPMs. Didn't sound anything like your clip though.

 

went to the dealer today. they said i need a new muffler. they mentioned some baffles or something has come loose inside the muffler.