Engine shuts off when stopping, yellow engine management light turns on

Hello,

The issue you are describing sounds like a faulty crank position sensor. When crank sensor goes bad it can stall the engine. And it may or may not restart.
As the Opel is not sold in the US I am unable to provide you with all the details regarding to the replacement procedure. But the crank sensor is located typically next to the crank shaft pully, towards the bottom of the engine.

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

Since the check engine light is illuminated, the first step would be to have the vehicle scanned for the code(s). As that can help with the diagnostics.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please let me know of any questions.
Thank you.

Hi, I hope you can help me. My car is pretty old but hopefully you can assist. When I drive my vehicle, the yellow engine management light comes on and when I come to a stop street or traffic light my car shuts off and sometimes does not start on the first turn. I've replaced fuel pump relay, crank sensor and serviced the car but still. Please help me.

It still continued even after replacing crank sensor.

Have you scanned the vehicle for codes? Knowing the code(s) can help with the diagnostics.