i can assure u that this is not normal for the guy saying this is..i have used numerous different high flow cats and test pipes with aftermarket exausts and stock exhaust and never had a rattle sound..u must have something rattling around on decel..get under and shake the **** out of the test pipes and the rest of the exhaust and duplicate it and track it down...rasp is one thing..something banging metal to metal is not normal

 

Like others have said, the rattling is probably the heat shield or rasp if you're not used to hearing it. If you have a stock exhaust (or even aftermarket, I guess), it could be a muffler width piece that looks triangular from the side that's there purely for aerodynamic purposes. That thing comes loose and rattles a lot.

As for the CEL, you just need a non-fouler. You can get a mechanical one that just raises the sensor away from the piping, or you can get an electronic one. They both do the same thing, and they both work great. Only the electronic one, well, it's electronic so it can and will eventually burn out.

 

OP, does the noise sound like this?

First heard at 0:33 in.

http://youtu.be/Qxn2_54EXDQ

Edit:

Blah. I forgot how to embed videos on GDriver. I'm used to doing it on another forum.

 

Does anyone know how to get rid of this noise? Would a 2.5in Y-pipe solve the problem? Or is it the headers?

 

I've heard the noise will be reduced if you get a Y-pipe. Not sure about the headers.

I think the sound is kind of amusing. I've had a few ricer kids ask if it was my "blow off valve."

 

No doubt it's amusing to hear what other people think it is. In fact, my ricer friend asked me if it was my wastegate....

Anyway, I think I'm going to get a y pipe to try and get rid of it. Anyone recommend the Megan y pipe?

 

Megan's test pipes are decent. I don't know about the quality of the y-pipe. A piece that big, I'd suggest Motordyne or another company that uses quality parts.

Things like test pipes are a dime a dozen, and aren't expensive to replace if they rust through. Y-pipe is a bit of a different story.