P0420 Engine code

My 98 Protege ES 1.8L, engine light started coming on. The shop says it's the O2 sensors (front and rear). The way the thing runs (uphill really loses power) I think it's the catalytic converter. Does anyone have any experience with this error, and it's resolution? Much Appreciated.

Well... After the shop replaced both the front and rear O2 sensors... about 75 miles later, the engine light came on. Another trip to Autozone revealed the same P0420 code. Back to the shop and they replaced the catalytic converter. It's been a week and so far alls good.

I had the same problem with mine. I have not gotten my catalytic convert replaced yet, but i had to rule a bunch of other stuff out first because at first when my engine light came on my dad unhooked the battery and cleared the codes, light finally came back on and the code said i needed to replace the catalytic converter. I think it's pretty much gone now, ive lost a lot of power driving and stuff so i think it will greatly improve everything