ok...you know the injector clips how they are in a line...sometimes you bring it in from the wrong side of the motor, thus you hook up the clips to the injectors back words.....so isntead of the injector clips being clipped 4-3-2-1 they are clipped 1-2-3-4 this would make the injectors fire at the improper time compared to when the motor was on its firing order...thus why it would sputter and pop and want to start but not.