I used the search function and saw that many people experienced rattles after a y-pipe install or a cat install. Well, my exhaust is stock except for headers and catback. Catback was put on a year ago and I haven't had any problems with it.

My headers were installed this weekend and now there is a significant rattle/vibration.

The car feels much faster, so I don't think there is a leak. It sounds great, exhaust note is coming from tail pipes, not under car.

The vibration occurs right at start up. This morning it vibrated for about 10 minutes at idle, then went away. As soon as I started driving, it came back. Vibrates on acceleration, gearing down, and at idle when I rev it.

With the hood up, it sounds like the noise is coming from the header "area". Yesterday I let my wife drive the car and I drove in the lane beside her. The noise sounded like it was coming from right behind the wheel.

What can I do to trouble shoot before I make the 70 mile drive back to my tuner?

THANKS FOR ANY HELP!

 

Maybe your cat bracket? Besides the headers and the exhaust's rubber hangers, that's the only other likely point of contact.

I to had some first-time vibration after installing my DC headers this weekend, only under full throttle ~5K I could hear a slight rattle. During the install I noticed the SS headers flexed easier than the OEM cast iron ones - another source for more movement and possible contact/rattle.

Turns out the cat support bracket (which is useless after installing the poor fitting Kinetix cats 6 months ago) was close enough to the cats after the header install to possibly come into contact with them.

 

You still might want to check the rear brace, where the y-pipe bolts up to the exhaust. . since you have the cats and now the headers, the anles may have changed causing this to rub.