You live in NJ. Is there not a second dealership or independent shop you can go get a second opinion at? The reason I ask is since you have already complained multiple times before your CPO ran out, and the dealer couldn't find anything, you may be covered still under that CPO if the second opinion finds an issue.
EDIT: I drive the piss out of my car and I burn close to a quart every 8-9k miles. Acceptable to me, but yours seems much more severe and I wouldn't rest until I found the issue.