I have email contacts in my Yahoo mail app that were deleted from the web version (I haven't synced with the web version) If I do sync will I loose the contacts from my phone (I dont want to loose them)
It really depends where the contacts are stored. If they are stored in your phone, then even if you sync, they will not get deleted, but if they are stored on your Yahoo account, then as soon as you sync, they will all disappear.
To check where they are stored, go into your regular contacts app and find a contact that also has an email address with Yahoo. If under the contact, where it says connected via, there is just the Yahoo logo, that means that the contact is there through the Yahoo account, and therefore it will be deleted as soon as you sync your contacts, but if it has a Sim card icon or a phone icon, then it means that it is saved in your phone/Sim and will not be deleted.