Nissan quest intermittent missing possible ECM issue

[07Nissanquest]

For past 5 months have been dealing with a strange type of issue. Van starts fine and runs fine, after turning it off and turning it back on (usually if less than an hour) van starts to miss on cylinder 3 and runs horribly with check engine light flashing. If sits for an hour+ and start again, everything is fine and light goes away. Dealership can't pinpoint the issue. Waste of money there.
All new coils and spark plugs. Replaced #3 twice with no resolve, injectors checked and cleaned. Whatever it is appears to be electrical. Somedays it has no issues at all. Removed and checked ECM. Anyone experienced similar issues or possible fixes? 124k miles, kept it well maintained since purchasing at 50k miles. Never had any other issues.

[VStar650CL]

Do you get any white smoke when it acts up, particularly right after the engine starts? If so, I think I'd replace the #3 injector just because. It sounds like it may be intermittently sticking open, and that's a mechanical condition which will be hard to test.

[07Nissanquest]

No smoke at all and if the issue lasted longer, which hasn't happened in few weeks, disconnecting ecm or battery for 10 minutes fixed the issue 50% of the time. Can start and drive now for hours, stop for a minute and turn back on and issue will begin. Never happens while driving either, only after turning it off then on.