Can anyone lend some knowledge on which color dot comes on these fuel injectors? Is it blue or black? Long story short I purchased some supposedly OEM Hitachi injectors off of Rock Auto to fix a P0302 due to a dead injector. I ended up purchasing all six new injectors and discarding the old ones without noting the dot color. Now, my Xterra runs really rich and is getting about 9 MPGs, has a prominent raw fuel odor upon start-up, and has an intermittent P0300, which I never had before. Additionally, I know have a hard start issue when the car is warm. The date of manufacture on the door is 01/01. Any help is appreciated, thank you!