I have a 95 Isuzu rodeo v6. While driving the engine will run rough and stall. Black smoke will come out of the tailpipe and there is a gas smell. The check engine light will come on and the drive gets better until it goes off. No error codes are recorded. Could the computer be failing or is there something else like a loose ground that could be causing this problem. I'm also having problems locating the PCV there is a connection on the left valve cover but no removable valve just a metal post that the existing hose is connected to.