PSD needs help

[truck26]

My 06 is still running like crap. While idling it drops down to a lower idle and sounds like its going to stall and then tries to compensate and goes to a higher and then tries to stay at normal idle speed. Sometimes when coming to a complete stop with my foot on the brake the truck's idle drops again and seems like its going to stall. Then while driving it seems to be missing or sputtering lightly while maintaining a constant speed. I plug my truck in at night and add Diesel 911 in at every time I fill up. Temps are only are 30 to 40 lately. If any one has experienced this problem or has any help I would appreciate it.

[Diesel_Diagnostician]

The only direction I can head you in right now is scan it for codes.