My 2001 mustang has been making loud noises from under the hood, it bogges down and then dies on me. It doesn't die in park, only in D or N. The mechanic says he doesn't know without a "code" from the car. First we thought it was the cam shaft sensor now I am being told it might be the synchronizer. I can't spend money on guess work. Can anyone help give suggestions on what it could be?