Got the 97 Sub SLT fixed...strange

[chargerrich]

Ok so I posted earlier that my 97 Sub would not start and was producing a "heavy crank". Turns out the Cats went out and apparently literallly melted the O2 sensors.

So I replaced the O2s (both) and also went with a magnaflow Cat forward instead of an OEM. This provided me better low end and was actually cheaper. My real question however is WTH caused the O2s to melt? I am running a hypertech (have it stock now) but other than that I cannot figure out what would cause this.

Any ideas?

[MrShorty]

Pre cat or post cat O2's or all 4 that melted?

I've heard of many cases where there is a lot of excess fuel in the exhaust that causes cats to literally glow red from the heat. Excess fuel also plugs cats up. So I expect that they just got that hot as they plugged up.

Any sign of the engine running rich now, or signs of excess fuel in the exhaust stream?