My stock 01 6.6 is idling at 850, it should be at 600. So I bought this 01 about a week ago, its completely stock with 216k miles, it's been very well maintained. But i knew it had this issue but I did some reading and it sounded like a easy fix, but everything i have tried has not worked. I have put in new thermostats, new MAF sensor, new temp sensor and plug and it still idles at 850 and occasionally shifts hard from 1-2 and 2-1. I'm not sure what else to do. Any suggestions would be great! Thanks!