why is my car dying out on me while driving? on 2002 Mercury Sable

i have taken it to the technician their answer is that there
is no codes or flashing lights on, so they say its not wrong. that i should drive until it will no longer start the
next time it goes off.He had no code to give me. so what could be the probelm?

Asked by for the 2002 Mercury Sable