I'm not too familiar with Toyotas as all I got here are Fords and GMs. It could be a censor problem. Could also be something stupid like gas cap.

I don't know what its like in the States but if you're ever looking to replace that catalytic converter don't buy a new one. You can get them from part yards. Only trick to it is to call the yard instead of going to their website.

Anyways good luck. Good to see more car posts here.