there appears to be a vibration when i start my 355, after it warms up the noise disapears. any ideas, i heard that this is common.
Take a rubber mallett and tap on the cats.....if they rattle it is time to replace. (Once the catalyst rattles....it will brake up and clog your muffler if you ignore it..)
It can also get sucked back into the engine causing much worse. See Nightlife's thread about that. I'd stop running it immediately until its checked out.
Woohoo, a blessing in disguise if they are toast. Get a nice set of metallic core replacements. Pick a vendor, they all work fine. Me, I'd check with gothspeed to see if he'd fabricate a set for you. BW, there are lots of places your car will create this rattle so the cats are not necessarily the only and first option to explore. There are heat shields that sometimes loosen then rattle. There are vacuum valves and God knows what other parts that can create a metallic rattle that sounds similar to the cats dying. But if you rap the cat, either one, and it rattles or vibrates, change themt ASAP before the matrix breaks down any more and trashes stuff.
+1. And I am unsure of rapping on them with a rubber mallet is a definite test. For an extra 30 minutes per side, you can simply remove each cat and confirm it's condition. I would prefer that method. If your car has bad cats, the "check engine" light should also be illuminated. Does the light come on when you start the car, then extinguish once the engine catches and is running?
