Kia Sorento jerks and goes out while driving

Help, my Kia Sorento jerks short and just goes off while driving, after a few minutes he jumps again! at the beginning went off on the highway after switching off the cruise control, then on the country road after the cd player hung up and today just without warning what could that be??Please help me I was already in the workshop and they found nothing just said I should come again when it happens again!