Start problems with Omi A 2.0i

Hi, yesterday I bought an Omega-A 2.0i GL Diamant Automatik and at the same time have a rather disturbing problem: If I want to start the car, nothing works at all, only when I give some gas the car stutters. If I then drive a little longer it calms down, only it can happen that it runs out a little longer at the traffic light. Now I thought, well, new spark plugs have to come here. These installed, the first few times started it went without gas, but with jerks. Later off he then the same problem… what can that be? THX 4 HLP!