Motot suddenly goes out – check engine

Hello guys, since this week have the following problem with our Saab 93 Cabrio YS3D. The Moto goes out suddenly and the check engine lamp lights up. The starter turns, but the engine doesn’t start. The workshop has read out fault memory and found many (volatile?) errors. But nothing concrete. And the engine then also jumped again. Guess now, since the tank was on reserve (90 km rest) that possibly dirt or air was sucked in and that had triggered the errors. N But last Friday the same thing happened to us again (tank was full) -> ADAC called. He couldn’t read the FS, but the car started again. And the check engine lamp flickered. What could that be? Greeting, Olli