what to check started,droveit,then at randowm engine dies on 2000 Saab 9-5

engine died while driving happened 3 times in the last 3 zone couldn't find any code

Asked by for the 2000 Saab 9-5
there scanner may not pick up all codes. seek a diag and est from your mech
realize that goes to saab in 4 days ty