already cleaned the MAF out. If the cat is bad then how does the car run?? every time I've had a bad cat, it was clogged and wouldnt let any exhaust through so the engine wouldnt crank at all.

It's just a pre-cat type thing as well. Thinking about punching holes in the two honeycomb passages...

oh and after I replaced the o2 sensors, the only code I got back was the P0135 code...not the P0430 code??

I posted the question up on b15sentra board already, I'll give this other board a shot as well.