I wonder if my injectors need to be replaced... My car is an early build 2010. I haven't looked at the Index number on the injectors yet, but I'm guessing it's probably 7 or 8. My car starts fine, usually fires up within a second or two. I installed a new muffler last week and after about a week of not washing the car, the inner tips were pretty black... pictures attached. My car still has cats btw. Is that a sign that the injectors are no good?
(i know the muffler was sitting too low, I've since installed the correct exhaust hangers and now it's perfect)