cats gone bad?

[97splorer]

How can you tell if your catalitic converters are bad? About a year ago I noticed that on of mine had a leak in it so I bought that JBweld type crap for exhaust and it sealed it up.

If my cats were bad would I know it or is there a way to check without ruining them?

Every now and then I can hear a rattleing sound kinda like a heat sheild or a thin piece of vibrating metal. It only last about 2 seconds each time I hear it but it is happening more frequent now. Is it time for all new exhaust? How much $$$ am I looking at to change it all out?

 

[mrboyle]

If your cats were bad you'd know it. You would notice a major loss of power, poor idle, lack of acceleration, etc...

 

[X~FACTOR]

What mr.boyle said plus I thought it does not filter the exhaust as much so smoke comes out with darker color. Am I correct on this?