Loss of power - catalytic converter?

[Stan944]

I need some advice guys:
After a few spirited runs approaching the redline, the engine looses power, and starts 'pur-pur-pur..', for a few seconds. It actually doesn't feel strong above 5 krpm at all. Something also rattles above 5 krpm.
I'm thinking the catalytic converter is clogged, and when it heats up at high rpm it temprarily gets clogged more (is it possible?), creates more backpressure. The rattling might be from broken pieces inside the cat.
Does my theory make sense?
FYI: I've had the car for about 60 k miles, and this might be the original unit.

[Jeff Laurence]

I had a piece of the cat break loose and turned sideways-- the engine wouldn't run at all above 3500 so , yes , you could have a piece broken inside your cat.
Jeff

[Stan944]

thanks Jeff,
I should have mentioned I tried a stethoscope, and unfortunately didn't hear the rattling coming from the cat. I don't know how conclusive it is.
I wonder if the rattling and the power loss are separate issues here?

[legion]

I gutted my cat, my car still has an underside rattle when I engaged the clutch too quickly at low RPMs. I think it is a heat shield somewhere.

[Stan944]

Originally posted by legion
I gutted my cat, my car still has an underside rattle when I engaged the clutch too quickly at low RPMs. I think it is a heat shield somewhere.

Did you have a similar loss of power at high rpm, and did it go away?

[legion]

I did have a loss of power at high rpm, but I also had a leak in my crossover pipe, and a bad blowoff valve that all got fixed at the same time--so it's hard to trace if gutting the cat did anything.