Yeah I know the first thing to be said will be search for it. But I did and didn't find my exact answer. I have a 2006 5 speed GT, put a prochamber on and only when cold does it vibrate so bad that it rattles. Now, your gonna say its because of the prochamber heating up or something. But my friend down the street has the same noise, but only has flowmaster axlebacks. It only comes from the passenger side. So I thought maybe it was the heat shield. Took it off today and it didn't do it while I had it jacked up. But when I took it out, it also does it when I come to a stop the first 2 or 3 times.Only on passenger side. A loud vibration that sounds like rattles. But goes away. While I was under the car when I first started it it didn't do anything so I couldn't pin point it. Where else is there heat shields that could be vibrating? And why does this only happen after exhaust changes. Does anyone else with only a prochamber have this problem? And why would i hear it when coming to a stop through the brakes? If anything can be answered that would be great. Thanks

 

Sometimes the low frequency of mufflers gets a vibration. (dash Etc.) But yours when jacked up it stops and lower it, starts up again. Sounds like the pipe is too close to metal somewhere. Go on ramps to get under or to a shop that has the type of lift that the car drives on and look/feel around to be sure you have a good gap around the pipes. They might just need a little twist to cure it. Good luck.

 

Left rear over axle pipe is very very colse to the support bar, check that, It was the cause of my same problem on my 06 auto with aftermarket axle backs!

 

Why would it sound like its coming from the passenger side front?

 

Ok, thats not it. There is plenty of room around the whole exhaust system. It rattled again while backing it into the driveway. Even after taking off the heat shield I thought it was. If there is plenty of clearance. Why would I be getting a very very loud vibration noise? And like I said in the first post, I've heard it on a car w/ the stock mid pipe

 

i have the exact same problem coming form the exact location....i first heard it when i had my slp loudmouth...then i switched back to stock to see if that was it but i still heard the same noise so its NOT the axle back.......when i went to get new tires i had the guy show me the car under the lift..we looked but NOTHING.....i am baffled.....im gonna check the exhaust hangers next week..i noticed that 1 hanger had a broken peice of rubber in the middle so maybe the metal pole from the exhaust is banging around the insde of the hanger..if i find that any of the piping is too close to the frame or any support bracket..im gonna tape around the exhaust pipe to cushion the noise...it sounds horrible escpecially when cold and i drive next to a divider with the pass window down..(you can hear the echo off the concrete)

 

I can tell you in my case that its not hangers. Because I shook the hell out of the pipes andyou can't hear anything. Are you getting the noise when you brake also? I checked to see if maybe the shield behind the rotor was loose and it wasnt. So if this is sorta common, how come no one has any fixes?

 

I have that problem also, it only happens while cold though. I took off the 4 heat shields and it has continued, mabey the connections on the H pipe?

 

But why would it happen on a vehicle that has not had an mid pipe change? It's very annoying and people who don't know about it think theres something wrong with our cars when they hear it

 

I ALSO HAVE THE SAME PROBLEM. ESPECIALLY WHEN I FIRST START THE CAR AND ITS WAMING UP, AS THE IDLE COMES DOWN, ALL HELL BREAKS LOOSE. RATTLES SO LOUD PEOPLE LOOK AND THINK WHAT THE HELL IS WRONG WITH THIS GUYS CAR. ACTUALLY, I CAN LIGHTLY KICK THE TAILPIPE (DRIVERS SIDE ONLY) WHEN CAR IS OFF AND HEAR THAT ANNOYING SOUND.
I ALSO HAVE CLUNKING WHEN I DRIVE OVER BUMPS. CANT GET THESE JBA'S TO SIT RIGHT I GUESS. I MIGHT DRIVE TO SAN DIEGO AND SEE IF THEY HAVE SUGGESTIONS OR HELP PROPERLY INSTALL THEIR OWN MUFFLERS AT JBA HQ.