the little black thing that is around the part where the injector sprays is cracked....is this bad? or do I not need to worry about it

 

don't worry about it.

 

As Spencer said, don't worry about it. Your injector will perform the way it shoul;d without that cap. It's basically there to keep dirt and debris out of the pintle of the injector. So, try and keep it clean but it will still work fine for you.