NG Standby gas problem

Hello community, I have a complete problem with my stand gas speed. -> drive with the car… Speed normal -> car parking -> start car (speed I.o.) -> after the start briefly get into the gas and leave out again -> car died. -> After starting immediately start off and then off the gas -> stand gas again at 900 rpm so I have the problem only when the car has stood and I leave it and just around stood still with the gas… or also (since I play with the gas) automatic) when I put D in after the start and just walk off the brake -> car dead… If I give gas however and then stop at the next outlet about 50 further nothing is missing.. What could this cause? Fuel pressure storage? Fuel pressure regulator? Idle engine is new as well as empty running hoses… Underpressure hose for VEZ control unit also I.O.