It's still under warranty
And if we make any changes or alterations, it could void the warranty. We've had it at 2 different garages.
The plug wires, plugs, air and fuel filters, and everything else that you mentioned have been checked. The mechanic that last checked it yesterday, called the Ford plant in Michigan to see if a fix has been found. Ford has given an alert to the dealers that there is an idling problem, but they've not yet figured out why. It's not been turned into a recall yet. The specs for the truck say to use 87 octane, nothing higher or it won't run right. We've only used 87.
We've checked the seat tracks, and there's no reason why it shouldn't move that we can see. The mechanic said the same thing.
With only 10K miles left on the warranty, we'd like to find the reason and get it fixed before the warranty runs out.