I have heard that the new diesels, Dodge I know of for sure, aren't supposed to idle. This is a MAJOR problem for me and I need to get a new truck for work. I really don't want to shut the truck down when its below zero and I am working! Thanks!
What thats talking about is you don't "have" to let the engine before shutting off. The reason for the idle before shut down was the theory the tubo needed to slow down. With new technology that is no longer needed.
So buy your Dodge and let it idle if you want to.