Two things you might look into that can have a great affect on HC's in the exhaust at the tailpipe:

O2 sensor - tells the engine how much oxygen is in the exhaust stream. You need a certain amount of oxygen in the exhaust for the catalytic converter to do it's work of converting NOx and HC's.

Catalytic Converter - If your Cat is dying, you will measure higher HC's or NOx at the exhaust pipe. Most are honeycomb type units that have two separate catalyst structures in them. The honeycomb that works on HC's might be the culprit.

As usual with a Toyota, make sure the TPS is adjusted properly and the timing is set as per the FSM.

Any other mod's that you have done?

Good luck,

Mike