iPhone apps not syncing!

I previously had an iPhone 3GS which dint sync apps in itunes (It does not remove the apps,update them or add more,itunes just skippes that step). Ithought it was beacause I messes up the settings.So now i have an iPhone 4S which is restored from backup of my old iphone.THE SAME PROBLEM STILL HAUNTS MY NEW IPHONE . Ive tried evething including transfer purchase,reauthourizing accounts and restore.PLease Help Me i have no other way know but to re-download every app on my itunes.I dont want to restore and set up as new phone because i will loseall of my precious contact.THANKS IN ADVANCE