Rattling Cats??

supercoupe92FL

Registered User
OK so my car has been making a weird rattling noise whenever it is under load regardless of engine RPM or what gear I am in. But it wont do it in Neutral, only while Driving. I looked up on the other related threads and it seems like this noise should coming from the cats which would make sense, but is there anyway to know for sure? I wiggled the heat shields around and they didnt budge or make noise and I tapped the cats with a hammer and didnt hear any rattling either.

Also, I'm gonna be taking the car in for NY state inspection soon and its gonna be needing emissions test done now that I am living near the city, any magic tips to pass?? SHould the engine be warm/cold? Any fuel additives that will help it pass?? Obviously if my cats are shot it wont pass no matter what, but if I can scam my way thru it, it would save me some $$ for another year.

I appreciate any help!
 
On the stock cats it's usually the corner of the heat sheilds that come loose, where they are welded to the cat. So you'll need to pry them with a screw driver to see if the shield lifts away at the weld. We also have full (CA style)inspections here in NJ; so I would make sure the car is well warmed-up and a bottle of one of those "guaranty to pass emmisons" fuel additives can't but help. I just went thru myself and although my NOx was well within limits, my HC just passed !! and, that I believe is was because I still had my summer fan hook-up (with the low speed running all the time), so the water temp was only just around 200 F.
Good Luck
 
Ok thanks for the input, I'll doublecheck the corners of the shields again to see if that is where the noise is coming from. I have my fan wired with a manual switch so I will be sure to have it on when they do the test.

You're from Cherry Hill, My g/f interns for NFL films and theyre headquarters is right near there. Nice area.
 
There's a heat shield on top of the resonator. I'm not sure if that could cause a rattle.
When my old car had a tinny rattle, the first time it was caused by the cat heat shields and then a couple of years later by the cats themselves.
 
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