Ok I am currently changing my orings around my injectors because I had a bad leak. I took my injectors out and I found like some carbon build up no them."black soot". What I was wondering is why my injectors are out should I clean them up with some like fuel injection cleaner or is it not good to do that. Also what do I need to watch for while doing this. Thanks.

 

its normal from oil vapors inside your intake manifold. use a little brake cleaner on a damped rag and wipe it off.