Default I need help, no signal or data after flashing any non-stock rom

Every time i flash a custom rom other than stock I don't have any data. I can provision if i have wifi on and update profile and prl (im on sprint) sometimes i get 3g signal but its virtually non existent. It says that it cant connect or no data available even though it shows 3g or 4g. It only seems to work with my nandroid backup of the stock rom. I have used custom kernels and still same issue. only tried 4.3 roms basically the ones with most views. I have check all me settings and seem to be ok. Any help is appreciated.