I have replaced the number 2 injector and now it will not even start any ideas on 1993 Nissan Altima

before replacnig the injector it ran rough, removed the #2 plug wire and the vehicle idle did not change

Asked by for the 1993 Nissan Altima
did you check the compression??
you also need to check the fuel pressure. go back over your work and re check to see if you left something undone.