This Thread is for the 6.0 Jumped in the 6.0 to pick up a trailer for work ran great for 20mi then started idling really rough and wants to fall on its face between 2800-3000 rpm right around when it should shift, this truck as been stored for about a month and a half I was thinking it was bad fuel or a plugged cat but I could be wrong any ideas on what this could be??

May be fuel filter!:)