He said when it starts up he has to keep reving it at about 2000 rpm but when he lets off the throttle the car shuts off. Anything in mind ???

 

There is a secondary fuel module(don't know what it is called) mounted on a bracket on the top radiator support that may have gone/going bad. That happened to me, but within a couple of days, the car would not fire up at all. What year SHO? If you are getting spark, that is what I would look at.

John