JLBRIZ

Hi, this is my first post in this forum and I came because I have a weird problem with my nissan. every day my car was working well until one day walking switches off after 20 minutes I start it, the next day will not start if there is spark at the spark plug. and all day I could not get it to start. The next day I try to start it and it started on the first try, use it all day and it worked fine. But the next day will not start, but if I put gasoline direct the air flow starts at the time then turns off. The relay seems to be well. the computer has power but no pulse at the injectors, and check the electrical connections and all is well. It is about the temperature sensor to the pulse of the injectors? why a day starts well and the next day not start?