Toyota Repair: emission testing, fuel hydrocarbons, intake leak

Question
My car failed in emission testing due to high HC in the 40 km/h test. It passed CO and NOX in both idle and 40 km/h test. The acceptable range was 0-68, my car scored 73.
I changed the oil, the spark plugs and the PCV valve with no luck ( it scored 75).
The cur runs great with no problems what so ever.
Thanks

Answer
HCs are unburned fuel(hydrocarbons) this is usually caused be an engine misfire, the engine is not using all of the fuel it takes in, this may be isolated to one cylinder or all of them, this could be caused by a misadjusted valve or leaking valve or an air intake leak or an electrical misfire, to be able to help more I need to know what yr/model/engine size/and mileage on the odometer.