My truck ran great til I moved to Florida. It started having cold start issues in 65 degree mornings. I ghosted this forum and found threads on stichtion. Thought what the heck I would try REV X. I found it online and thought it was too expensive.
I got back on the forum and searched aternatives to REV X. Wound up ordering ARCHOIL 9100. I changed my oil and added ARCHOIL. It took about 3 days to completely clear my stichtion issues. I have 165k on my engine so I am just guessing that it might just be a temporary fix for injectors that are wearing out. Only time will tell me I guess.
I had good results with ARCHOIL so you might try that if REV X seems too expensive. Hope you get it sorted out. These 6.0's are an ongoing learning experience.