[darkpuppet]

Hmmm.. I've been in only 1 other person's focus running stage 2 cams...

and his car threw a cel...

then I gotta wonder what's up with your timing and fuel enrichment that is toasting the O2 sensor with that kind of frequency.

You need to hit a dyno with wideband O2 and see if the commanded air/fuel is what the car's really doing... if not, especially if you've richened the mixture in closed loop (over 4k), you may be experiencing a MAF problem... oil coating on filter could foul it, force the car to run the failed tables, and under heat, those tables are useless.

if, after a couple of runs you can confirm the command a/f is the same as what's coming out the tailpipe, you can go back and see what you can do about the O2 sensor...

after all that, I gotta wonder what you're doing blasting down the 401 at 180km/h .. and doing it that frequently... we're all susceptible to the odd moment of immaturity, but if this is your standard practice, you need to cool it down before you kill someone or yourself.