Catalytic Converter help

I have a 1999 Ram Van with the 360 5.9L with just 97K on her. How can I tell if the catalytic converter is bad. I noticed a rattle from under the van like a loose heat shield but that is not the case. However while inspecting I noticed that the cat rattles when i pound my hand against it. I am definitely experiencing a performance problem while under load especially when engine is warm. I have performed all of the necessary tune-up replacements including O-2 sensors but to no avail. Any advise will be greatly appreciated.

If it lags at around 2,000 RPM and it feels like it has a top speed of 25 MPH, then you have a bad catalytic converter.

Thanks for the quick reply. Am I supposed to hear a rattling sound coming from inside the cat when I bang against it?

If you hear that banging sound, that means it has already filet-ed itself on the inside and it's done for.

That is what I thought too. I will start pricing a new one tomorrow. I'll keep you posted. Thanks again.

Should be some interesting prices.