You might run into a problem with your warranty company with them stating that the engine, although not working at 100% efficiency, is not BROKEN. And, therefore will not cover it.

Been there with a dying turbo. I was told that it wasn't dead. I came back and said that if it does fail, it would take out the engine and theat would cost them more. They said if that happened, they'd worry about it at that time. You see my (and their) logic here? Good luck.

I would recommend you have the Service Manager, or owner, state your case for you. Not the mechanic.

__________________
///BRUCE