Just thought I'd let everyone know what I found was causing my 2016 F150 coyote to intermittently die at idle. The problem first started in 2018 and at about 100k miles after the warranty was up. It never threw a code and ran perfectly otherwise for the next 50k miles or so when it started to hesitate to downshift and shutting off got more reqular. I spent countless hours on the internet with zero results. There were quite a few posts about the same problem, many of them more severe, but I couldn't find a definite solution.
I did start to notice that as the oil life percentage got lower the problem got worse and then better as soon as I changed the oil. I took it to the local Ford dealer where they kept it for three days and charged me $300 and found nothing. Last month it finally threw IIRC PO022 and something like "bank one, cylinder one exhaust retarded".
I searched the internet again and found a YouTube video that said it was the VVT solenoids. The Ford dealer quoted me $2,300 to change them out. Instead I bought the solenoids from Ford for $41 each and replaced them myself in about 4 hours. The exhaust valve solenoid nearest the oil filler cap was covered in surface rust.
It no longer dies or hesitates downshift. I didn't know how bad it was slowly getting until I changed the solenoids. I runs much smoother, pulls harder and gets 1 or 2 mpg better mileage.

 

You might want to consider changing the oil more often.

 

I’d suggest putting a new oil filler cap on. Or at least a new seal/o-ring for it.

the “extra rusty” tells me there’s an air flow there unlike other locations.

 

Thanks for the info! How much of a pita was it to change the solenoids?

 

Changing oil more often? I've been changing it when it gets to 25%.
O ring? I did put a new o ring on the filler cap when I changed the VVTs. It was no better than the old one, but correct it was getting moisture inside.
PITA? Nope. I only had to move one wire bundle out of the way and I didn't remove the dip stick tube from the valve cover. I did have to tap the sides of the valve covers with a rubber mallet to loosen them. It only took 4 hours.

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Thank you for sharing a cure. Too many times people ask a question, then find a fix and never report back.

 

Ditto this.....

 

Moisture
Do you have to occasionally add radiator fluid?
Do you make many short trips where moisture doesn't get a chance to evaporate.
Has anyone ever changed your thermostat to a lower temperature one, not recommending that. Cooler running motor could take extra time to evaporate moisture.

 

Nope, I haven't ever had to add radiator fluid.
Nope, no short trips either. I live 35 miles from the nearest town so I'd say 85% + highway miles.
Nope, it has the original thermostat.
The only thing that has been changed is the battery, the spark plugs, the rear brake pads and now the VVTs.