High HC is usually due to unburned fuel, or sometimes due to oil consumption. Usually, when the HC is high from unburned fuel, the CO is high too. Where was your CO? Does the car smoke any from oil consumption or have oil deposits on the plugs? The catalytic converter's job among others it to burn the unburned HC that is normal in the exhaust. So to pass emissions your engine must not put out too much HC, the catalyst must burn what HC is put out, and there can't be additional HC from oil consumption.

So there are three likely scenarios:

1, your fuel mixture is adjusted too rich , or is runnig too rich from a malfunction

2, your engine is burning oil causing high HC readings

3, your catalytic converter may have lost its efficiency and isn't burning the HC