My Dad had an 82 FJ60 he towed a small pop up tent trailer with it just fine but when he moved up to a bigger HiLo trailer that was much heavier the 60 wasnt happy.  The way he figured it is if he was going to tow he needed something that could so he traded up to a 91 Jeep Grand wagoneer.  Gas mileage was terrible no matter what.  I think with some mods the FJ60 would have done a better job and improved MPG but he didnt want to mess with it.