Tire size as well as tire inflation, Rear end lubrication, Winter fuel mixture,New air filet may be of different brand and not allowing as much air.
Seafoam could have also loosened something causing an injector not to flow correctly
I would check the tires and account for fuel mixture as well.
My motorcycle gets 40 in the summer and 36 to 38 in the winter.
Don't go by overhead reading especially if you changed tire size. All terrains as opposed to regular road tires will use more fuel
Air up fuel up, drive safe and be happy shes running well.
Not to be an *** but did you get a jeep for fuel economy?