I have black soot on the tail pipe of a 09 Toyota Tacoma 5 speed 4wd reg cab 2.7. This is not a change, its been like that since new. It runs well, 35k miles, 22 mpg. No codes. toyota has hooked it up to the computer and all is well. Oil consumption between oil changes is nil. There migh be a slight darkening of the oil at each change every 5k miles. I do have to scrub the black soot off the side of the box every few weeks.

Toyota techs and computers say all is fine. Any experience from the group?

My 04 v6 has a clean tail pipe, not so long ago my 90 v6 had a nearly clean tail pipe.

 

I believe its a byproduct of combustion. each car and motor combo will produce different amounts.