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?