Chevrolet Repair: sick 3.1, vacuum line, o2 sensor

Question
hi james i was an expert on this sight for a few years,but i have hit a roadblock on my wifes chev celebrity,3.1 engine.it started with a check engine light coming and going for about a month,but i did not check for codes.last week it started missing and blowing black smoke out of the exhaust and it quit running.i did manage to get it started but it is missing and it acts like i have a restriction in the exhaust.i did change the fuel filter and the o2 sensor.i plan on putting new plugs in tommorrow.please help me out  i have been away from engines for a few years with some medical problems.thanks in advance clayton .

Answer
If you are getting black smoke, sounds like you have a fuel issue possibly from the injectors.  Check the wiring under the intake, as well as the regulator.  When you do get the car running, pull the vacuum line off the regulator and see if it clears up.  If it does, it may just be the regulator.  When you pull the plugs out, see if one or more is soaked in fuel.  That would be the first injector to go after
Jimmy