My 02 4.7l catalytic converter broke up and started rattling like crazy. I got a bout 10 miles on my new one before it broke up and did the same. I was told that it's something to do with the engine burning too much fuel. After the new cat was installed and went bad the check engine light came on, went off for a while and came back on again.
Any ideas?
Thanks.

 

Did you get it covered under warranty? I think that emission stuff is good for 80K miles.

 

The truck has 99k on it.