2002 Toyota Celica GT: Error P0420 (Catalyst Efficienct low bank 1)

[drewmerl]

When it rains...I can't wait to see what fails next.

Similar to the post here, I am experiencing this problem as well. I took it to a local mechanic and he said that it was more than likely due to a fuel leak on the exhaust as we could smell fuel in the passenger compartment.

This has been going on for about two and a half months. The first month the engine light was off and on intermittently for a few minutes. I took it to Pep Boys once and it didn't even go off the entire time. No performace changes or engine code.

This month has been different. The MIL is on and as of late stays on. The code is P0420. There is a hint of a fuel odor coming into the passenger compartment and the performance has been rough. Fuel economy is down in city driving, no leaks under vehicle though.

I would like to do this myself since I am on a budget. I know if I went to the dealer they would gouge me at OEM prices and a nice dealership premium. I figure I could replace the fuel line, manifold gasket, and O2 sensors in order. If all else fails I can put in a new catalytic converter since it is a direct fit.

What do you think?

I should add I have been driving my old Probe around lately so i don't cause any long-term damage.