2000 Chevy Express fuel problems

Van will not start unless I spray stater spray in the mass air flow body. Van will run ok after starting. Does have a some performance issues does not go into passing gear like it should. Have changed out the fuel filter. I can hear hear the buz most of the time when I turn the key on. Pressed the stim on the fuel rail gas shoots out like its got plenty of pressure. Test says lean fuel, bad Mas airflo(have change out MAF with a used one same problem} have same problem if I take MAF Unit and hose off of Throttle body. Wont start unless u spray somthing in engin. One spray will make van start about 5 consecutive times. If done close together. After it sits for a wihile it will just turn over strong but not start. Thanks you very much!