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

[Bitter]

you don't measure resistance, you watch the sensor switching which it won't if you're running rich. Check for high fuel pressure and see if you can borrow a scan tool to see what your long and short term fuel trims are. I don't think you have a MAF sensor. Does the engine ever stumble or stutter or run rough? That's classic engine misfire damage or just very very rich.