White Smoke Only When Letting Off The Go Pedal

[FFR3247R]

Truck recently tuned. HS mini max on the mild setting. DPF/DOC delete. Has been on for 400 miles with no prob.

Today I drove it @40 miles steady and noticed when I came into town white smoke. Accelerated away under moderate power and no smoke. Moved my tune to stock and same thing.

Called Zack at Performance Diesel? I think is the name. He had me uninstall the tunes and reinstall. No change. Do I have a cracked EGR cooler? How do I verify? Can I just block it off?

Any other suggestions.

[04hdfatboy]

if its an egr problem i have an egr delete that gets rid of the coolers. PM me if interested.

[FFR3247R]

Anyone have a idea?