Cabe

Jim... Been thru all that, no codes and the truck still runs great. Has burned a quart in 1100 to 1600 miles since new. Gangly... thanks for the response. I purchased the truck new, this all started at about 55000 miles. Nothing odd about the coolant tank either as I was thinking about that as well. Last week was the most I have seen the smoke. Twice at a start from stop and once while driving. All in four days. Each time a considerable belch of bluish white smoke. Each time only a couple of seconds, but a good cloud. Since the truck is still under a warranty I have been pushing to get them to look deeper. Appears if they see nothing with diagnostics they have nothing to report and they have not seen the smoke, I understand that. Had different dealers give me different answers about the rough idle too, one said it does not sound right and one said that 6.2's do that... have not been back to talk to him. Like I said the truck runs great... my real concern is the periodic smoke then the rough idle. Thanks for your input.

Thanks for the response... I have tried that with nothing to report. I have never had any smoke at start up. Today was one of the roughest idle days I've had, but no smoke belch as I was expecting to see.

I purchased this 2019 new and for the first 50K miles it has had zero issues. After about 55K miles I noticed a slight rough idle like a misfire but it was not 100 % of the time. After about 60K miles it was more often and every now and then (approx once every couple of weeks, that I would notice) I would see a belch of bluish white smoke at take off, (like from a stop light or stop sign) then it would go away. Truck is now at 65K miles and it all happens more often. Yesterday I noticed the largest blech of bluish white smoke as I was driving (approx 50 MPH). Most of the time it does not blech the smoke and it runs great all the time, other than the rough periodic idle. I've had it into the dealer and they say nothing is wrong (or nothing showing in diagnostics). We are working thru an oil consumption test as the engine will burn a quart in 1000 to 1700 miles. What I am really concerned about is the belching smoke. Does anyone have experience with this or similar? THANKS, Chris