Hi,
I'm sorry you're having such a hard time adjusting to TBird. It sounds like somehow he's gotten the upper hand in your relationship. Leaving him longer in the cage will not solve the situation and continuing to do what you are doing is not working either. Start a log and write down exactly what you do right before T-Bird bites... then what your response is. We need to understand what is causing him to want to bite.
It sounds like T-Bird was not handled a lot in the previous home, so you need to work with him to teach him and better socialize him. Take him with you to a room in your house that he's not really familiar with. This is called a neutral room because it is NOT one which he feels is his territory. PLace him on a T-Stand perch and practice the UP and DOWN commands with him. Do you have my African grey book? It will explain many of the basics of teaching your new companion. Greys are different from other species, so even if you already know birds, this book (and others) will help you better understand how to work with this species (African Grey Parrots: A Complete Pet Owner's Manual).
It is hard to advise on a bird board when we don't know what activity is happening that is triggering him to bite. I suggest that you consider having a few telephone consultations with a bird behavior consultant... either someone like LIsa Bono or someone locally in your area. You are at a place with T-Bird where you need to establish ground rules.
The bottom line is that it sounds like you really love T-Bird. YES. You can work through these, and even worse obstacles, when you love the bird and are determined to work it out. If you don't, T-Bird is probably the type of bird that would be sent from home to home, with few people caring enough to help him. Since you love this little guy, DON'T give up! A Bird behavior consultant can help you with tactics that will help you with T-Bird, as well as help you build your self-confidence with him.
PLease keep working at it. You can write directly to me at merlin@AfricanGreys.com
Blessings,
Maggie-