RE: Rough Running
Aileen, please read carefully the post that Mark Drillock just posted.  I
say this because I encountered symptoms that I could have described about
the same way you describe your problem.  I knew what most of my problem was,
a bad injector.  One diagnostic step I took was to disconnect the the O2
sensor.  That seemed to cure the problem EXCEPT gas mileage went to hell.
Finding and replacing the bad injector cured the problem in my case
Discussion with Mark (where he explained the problem to me the same as he
explained it here) helped in understanding what I was getting.  I was also
dealing with a slightly mis adjusted throttle switch at the same time and
that was contributing to the problem.
Start by disconnecting the O2 sensor to see if that seems to correct the
problem.