Nissan Tsuru 99 catalyst problem

Hello estimated, I have a Nissan Tsuru 99, which brings a catalyst in the mofle tube, I want to know if there is any way to detect if the catalyst is performing its function, since when I use this car at the time of turning it off it begins to smell of gasoline slightly, already check the hoses, the tank plug, and the tank and there are no leaks, and I have been seeing that there is a engine The car is moving, and instead of lowering the temperature it starts to rise to a maximum of 3/4

To check it you need to put the exhaust gas reading machine. In its optimal state it should mark you:
- CO: 0%
- HC: - 100 ppm
- O2: About 0%
- C.O2: 14-15%

The carbon dioxide measure gives you the optimal behavior of the catalyst, it must be in 14-15% whenever the rest of the measures is fine.