My jeep has a hard time to start and it dies while driving.

I have a 1999 Jeep Grand Cherokee 4.7 limited and
it started to tied on me while we're on the road. The
truck turn off completely when it did that. After a
couple of times turning off while driving it started
to have a hard time to start. I putting much had to
pump the gas paddle for it to start. And it smelled
gas really pad like unburn gasoline. After awhile
the didn't want to start at all so we took it to a
mechanic. He said that the barrier was no good
and the computer not work well from lack off volts.
So paid the truck seemed it was fix took it as soon
I turn it off when got home next morning it did the
same thing didn't want to start.  Took it back to the
mechanic n said I'll something else broke so check
and later same day call said it's fix. This time he
replied but fuel filter and fuel pump so paid again
took it home was driving good turn it off when got
home n start it again and it turn on. Look like it was
fix until the next morning it had a hard time to start
and turn off while driving. I'm out money and
mechanic reap me off. Need help what can be
please don't know whats wrong.