P0420+P0430 fault codes help

[michaelw6]

Hello Toyota techys,
sorry to bring this up again but I don't seem to have found anyone who has successfully found and repaired this fault, but I wondered if you can help.
I have oxygen sensor problems on the rav4 1AZ-FE,
error codes im getting are.
P0430 Catalyst System Efficiency Below Threshold (Bank 2)
P0420 17 Catalyst System Efficiency Below Threshold (Bank 1)
cylinder 1 misfire, cylinder 4 misfire.
all same errors every time I reset them and try again.
im thinking either the top two 02 sensors could be causing all these problems?
i have ordered these and they will be in tomorrow costing me £82ea+vat from euro car parts.
I have seen various other remedy's not explaining themselves very well, like cat gone,well can I test this? if sensors are dead any way of testing these and also read that they can be cleaned any ideas if this works?
any ideas welcome...
please help. I can see this costing a fortune to repair.

[michaelw6]

peeps does anyone have the software, drivers mainly cause i think there not working for the 'obd2 vag tacho usb 2.2' it worked for a while a year ago when i brought it but does not work no longer tried to reinstall it and cannot get it going.
As this reads fault codes and need it to reset the engine management light when i discover the faults with my rav.
\thanks in advance.

[Mick Hatzo]

I am afraid I can't help with any of your problems as my knowledge base is very limited.

However, what I do know is that you may find more help if you post your question in the 4.2 section. Rav4s with 1AZ-FE engines belong there (2001 - 2005 models).

[Dr. Dyno]

My only similar experience was with my 2001 Subaru Forester. Kept setting an O2 sensor code. Typically that would mean a bad sensor but on eBay I found a listing for a catalytic converter saying it would fix the specific code I was getting. I bought it and it solved the problem w/o changing the sensor.