Clogged Catalytic Converter Options

[barterj]

Last summer the first catalytic converter melted and clogged the second one. I punched out the second and replaced the first one since that is the one with 2 oxygen sensors connected to it. Since I replaced the cat I've put about 20K miles on my car. The cat. melted and got clogged again.

Does anyone know any reason(s) why this is happening?
-220K miles (2.2L)
-Engine is running at normal temp, never over heats
-Doesn't burn hardly any oil, maybe half a quart every 3,000 miles.
-It is eating gas, though i think that was from the cat being clogged and it needing extra to keep the engine running under the increased back pressure from the clogged converter.

Here is a pic of what it looked like before I punched it out today

[richee3]

I'd guess that eating gas is the cause of the dead cat, not the other way around. Running rich will kill a catalytic converter. Is your check engine light on? I would guess that the primary O2 sensor is bad, causing the car to run rich which kills the cat. Which probably throws another code from the second O2 sensor.