Please help.

 

You gotta give more than that...

Have you checked the MAF - do you have a check engine light?

Any other lights on the dash?

 

"Air, fuel, spark... something is wrong with one of them" is about the best answer I can think of without more info, lol.

Is the car dying after warming up? Does it die periodicaly but start again? So many questions.

If you don't give the mechanic more info than that it's going to be a big diagnostic bill, and needless repairs.