Ok, so have any of you had this problem? I start my 94 5.9 and get black soot out the tail pipe. If i let the truck run for a while, the truck will rev on it's own and that check engine light will come on. I have tried to scan for codes but the scanner said that it was unable to connect. If the truck runs long enough I get two black soot streaks in the street and the truck seems to guzzle gas. Looking for a little advice, hoping there is a quick fix.