I want to know if is normal that when zex wet nitrous kit fisrt get activated it goes to like 15,16s afr and in like 1 sec or 2 it reacts and go back to 11.5s or 12.0 afr ...
It can the that nitrous flow fisrt tham fuel but anyone have adviced of how to prevent it or everyone have the same issue

 

Yes, it's common to have a lean spike when nitrous is first activated. You can put a slight delay on the nitrous solenoid using a controller, if you're worried.