I live in Where cold should not be a factor. Upon 1st morning start up it runs VERY ruff for first 1/2 mile then no problems at all rest of day. I tavel alot. Only @ 1sty start up.
Runs ruff @ start up on 2007 Ford F-250 Super Duty
I would take it to the Ford Dealer, have them look at the Ford Technical Service Bulletin : TSB 09-7-11 and TSB 08-16-6. They both are related to hard starting problems with the 6.0L Diesel engine. Good Luck!