I do burn oil pretty consistently. I would say I have to top off my oil tank about once a month. It never runs dry or anything, but I do find it a little lower than usual, So I just put in about half a pint or so every month.

I think when I replaced one of my CAT's a month ago, the mechanic did say that I needed new O2 Sensors, but I don't have the money to fix everything at once. Looks like I will have to deal with the poor gas mileage for a while.
I am pretty sure that the extra weight of the armor, the larger tires and drag from roof rack all contribute to the poor gas mileage. (Also LEADFOOT) which I try to keep to a minimum.

Thank you everyone for your help.