QUESTION
 

hey i had a question for anyone that can answer it, my car runs great good power and everything but after reving to pretty much any rpm above 1500 when rpm begins to drop again it makes this weird sound like something is vibrating or rattling i checked my whole exhaust cause thats where it kinda sounds like its comming from ive pulled a bunch of crap apart trying to find where the stupid sound is comming from but i think im just passing over it ive heard other camaros and firebirds doing the same thing so maybe someone knows what the sound is.

thats just the crappy flowmaster sound :D :lolsign: jk man...

It could be a few things... One, it could be a heat shield of some sort, Ive noticed those rattle a lot, I just rip them off when they start rattling. Or it could be somthing in your engine bay... Its hard to diagnose without hearing the sound, but I know my a/c / accessory drive makes a pretty grusome sound, and I havent found out how to fix that yet ;) But, thats my guess.

could be cat, could be heat shields, could even be engine or trans mount

or it could just be your mind playing tricks on you

lol well im pretty sure it was my mind and it was doing it before i got my flowmaster exhaust and i changed the cat and i checked the heat shields but the trans mount was something that i was thinking too so maybe i should check that but its definatly related to vibration cause when i turn the ac on it drops the rpm just that little bit that i cant barely feel but it makes the sound a little louder too so im just thinking something is vibrating thanks for the help though

It could be your accessory.. mine makes a rattling noise whenever I mess with my AC

yea that makes sense but it does it even before the AC is on

does it sound like its coming from the passenger side back seat area? because if it does mine makes the same noise, kinda like a vibrating/rattling sound

I had that same exact problem. It rattled a little when I went over bumps ect..

Then it started getting worse.
And then anytime I was decelerating using downshifting the rattling got really really bad.

Well I found the problem finally just the other day. Turns out a plate roughly in the middle of the undercarage(sp) was contacting the bolt of a ring clamp around the muffler.

This plate is held on by 4 bolts, and goes across the muffler just aft of where the driveshaft meets the transmission. It doesn't hold anything up, its just a protective plate I think from ground objects.

I had driven the camaro on a really really bad dirt road the other day and looks like the plate got bent slightly upwards, causing it to contact that bolt on the ring clamp. I bent it back out and rebolted it on and it the rattle was gone.

If you've scrapped bottom in the past, its possible the plate got bent up enough to contact the bolt when the muffler starts vibrating a lot. (i.e when engine braking ect).

I'll break out the digital camera later after work if you want.

yep thats whats going on with mine, hapens everytime i come to a stop and its driveing me crazy please post the pic's

Ok here they are.

As you can see, the braket goes right over the exhaust just behind the cat. Right under the braket there is a circular clamp on the pipe with a screw tightener. That Screw tightener was hitting the inside portion of the braket. So we bent the braket out a bit and that solved the problem.

The only reason I found that was luck. When we took the braket off, I noticed the inside surace had a shiney rub mark on it that lined up with the screw tightener on the circular clamp.

While I was fixing that, I also noticed my O2 sensor wire was hanging down. It seems to have broken off its support. So I tie wrapped it back up outa the way. I dunno how much it was bouncing around and maybe clanging on stuff too.

http://www.digiphaze.com/images/camaro/IMG_0151.JPG
http://www.digiphaze.com/images/camaro/IMG_0150.JPG
http://www.digiphaze.com/images/camaro/IMG_0149.JPG

sweet dude ill fix that when i take my cat off in a couple of days.... thanks alot

hold on were is your cat at? is it behind the passenger front tire? im wondering if its the same because mine is a 3.4

Yeah. the cat is same place. All those pictures are looking from the passenger side.

ok sweet :thumbsup:

Yea i had that problem when i had my 3.8 i had flows on that it was the bracket underneath, i also was allways having problem with the rubber hangers on the back... i got sick of replacing them and just welded it on.