i know a guy who has a stock 07 6.0 that he only drives sometimes due to economy. so he took it in and they said the turbo was gummed up??(story is comming from my wife, no details) and due to the sitting it had caused the problem. they had to remove the turbo and clean it, they said it needs driven regularly and not babied to keep it from happening again. like i said details are not at my fingertips but this all sounds like a joke.