I'm getting a gnarly clicking/rattling sound during certain levels of acceleration as well as sense that my exhaust is getting blocked somehow...

How long do catalytic converters usually last? Is it dependent on mileage or lifespan, and what are some common symptoms of a bad/old cat?

 

i would assume mileage because... it filters the exaust gases that go threw..

 

pull the cat off and look through it to see if it's clogged...I've heard they will make a rotten egg smell when they go bad too, The cat should last at least 90K miles on an engine thats not tuned to run rich.

 

so no one's had a cat rattle on them?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pbink &raquo;</TD></TR><TR><TD CLASS="quote">so no one's had a cat rattle on them?</TD></TR></TABLE>

If you cat is rattling then it a sign that you're running too lean of a condition(High Nox). Hence the reason the mounting pad inside the cat is melting off the honeycomb brick inside the cat which is why the cat has that rattling sound. It's tumbling all around the cat. Check camshaft timing and crank timing is within specs and not overtly advanced.