When starting the engine, it sometimes happens that it starts on the first try. But there are other times that a kind of hit is heard and the car does not start. It is necessary to try many times closing the switch and, after lots of attempts, it finally starts. When the engine is demanded too much, it suddenly stalls; I then need to wait 5 minutes and it starts again. When scanning it, no error is indicated. Thank you so much to anyone willing to help me.

Good morning, I have a Skoda Octavia 2004 and the engine starts without any problems but the idle speed is not maintained. The car stalls or revolutions raise and drop continuously between 600 and 1000 rpm. Occasionally, it stabilizes but, when you stop it, the failure appears again. I would like to know if I need to change something or what is wrong with my car. Help me please, thanks.