robert hoagland

I searched previous threads on this common problem. It seems the fuel delivery system is the culprit. My 16 year old son has a 1988 190E 2.3 that has a hard time starting, especially when cold. After cranking the starter four or five times, it turns over, idles roughly for a minute or two, then hums like it is supposed to and he drives off. Recently replaced the plugs, wires, cap and rotor. He needs to take it to a mechanic for the fuel system stuff, but was hoping for some advice/questions to ask before bringing it in, and what possible parts/repairs might be needed. He doesn't want any unecessary repairs done-$$$!
Thanks for your time and expertise,
Bob