Chevy & GMC Vans

So my buddy just went to pick his van up from his mechanic(he doesnt like to work on vans for some reason). He dropped it off because once you start it, it sounds like it tries to die or surges. The rpms drop and the engine literally sounds like its coughing, revving high then all the way down then barely bringing its self back to life. After it warms up it runs a lot better but it still has the problem just not as bad as first starting it. The mechanic bill was roughly $1200 so you know the EGR valve has been done, new dist cap, rotor, wires and plugs were all replace, Idler Control arm as well. There are a lot of other weird things on his bill that made no sense. His mechanic told him it was done so we went to pick it up and still had this surging problem and the mechanic was off for the rest of the day. Needless to say he is done taking his van into mechanics and wants to fix it himself he and I just dont know where to start. There is a new fuel pump and fuel filter installed. I was leaning towards maybe the Mass Airflow Sensor? Im gonna go through his van to look for vacuum leaks but I didnt see any the first time I look.

Anyone have any suggestions or know what this could be caused by?

Any help is appreciated,
Thank you,
Derek

Not sure if the fuel spider and leaky fuel pressure regulator would cause this running issue. Search for those terms and see. Others will chime in I am sure.