it started about 2-3 weeks ago with a slight vibration rattle at about 3800 rpm. Then, it started doing it at idle too. Not, it's rattling when I drive over bumps too. Is this a sign of cat failure? I've never had to replace one.

Yes, I check the heat sheild bolts, their tight. Checked the header/cat junction and the cat/exhaust junction, they're tight too.

Finally, if it is going bad, replace it with a stock unit or an aftermarket piece? Cost not an issue but it's gotta be quiet and pass NY emmissions.

 

anybody? I really gotta get this taken care of. The noise is driving me bananas.

 

I had a rattle from 3500-4500. it was the cat. when I took it off a nice chunk was missing and I had to shake some pieces out of my muffler.

 

If you have a front upper strut bar you may also want to check the clearances for it. I installed a neuspeed bar, had a bunch of squeeking, turns out it was rubbing on another piece of metal. Just one more thing to check before you have to purchase anything.

 

nah, it's definitely the cat. Thanks JDMJunkie, I just wanted someone else to confirm that "this is what it sounds like, when cats die" (sounds like a Prince song) before I blow $200+ bucks.

Now the decision is, replace it with a high flow or an OEM. Random tech and Carsound are cheap, but don't seem to last long. If anyone has experience with these things, do tell.

 

its like mine most likely the heat shield is rattingly im taking my off today

 

I got my catco high flow cat for 70bucks from sumitt. The best part was it came the day after I ordred it.

 

I would check the heat shield first as well.

 

My boyfriend is having the same problem with his 99 SI. When we are at idle, seems like only when its raining that you can hear something rattling or knocking around and when you go from 1st to 2nd, then to 3rd it backfires. My dad is a mechanic and checked it out visibly and he didn't see anything not together. And its not the heat shield because mine was rattling and its not really the same noise.

 

Nah, I checked the heat sheild and the 2 junctions last night, all were cool. But yah, that was my first thought too. I guess as cats get old, the material inside starts to break up and drift around.

I'll let you know what solution I come up with BnEiAkUiTcY. Hopefully, I can find a quality replacement at a reaonable price.

 

What kinda cat is it? When did you put it on?

 

it's stock. Honda put it on for me about 130,000 miles ago.

 

I have a friend who has the Random Tech no problems to report with it I just put a testpipe on.. $30 fix