The Manual does say .031. The correct gap is .044.

I know, I have tried .031. This was on #90919-01164 aslo listed as K16R-U11. These are the O.E.M.plugs that are in the truck, when you purchase it.
I just installed yesterday, NGK BKR5EIX-11. These are Iridium center electrode, with a taper cut ground electrode.

I saw NO reason to change plugs every 30K miles. If, you have done this on a 2.4L, you know it is not a piece of cake.
The air intake passes over the two center plugs. It has to be taken apart to get to them.