Idles rough after replaced cracked head

I had a cracked head gasket so I changed out the head. when was it ran fine but smokes real bad before I change the head. now that change the head it won't. idles really rough it barely stays running and when I give it gas it bogs down and won't go anywhere. I thought the timing was off I checked it twice. Do you have any suggestions? oh and meninges idles really rough to sender only if I unplug the mass flow sensor the idle gets the idle goes about write speeds up and gets right and levels out, but then when you give it gas I take off or something it won't go anywhere but I can't drive it.