Let me just add on the vapor lock possiblity that I have never heard of this happening with a Toyota but a friend had an early VW Rabbit and they were having this same problem where in the middle of a long trip like 150 miles from home the car would start stalling and die. Well they figure out after sitting on the side of the road for a while that it would start back up and be fine for another 100 miles or so. They figured out it was vapor locking from a vacuum in the gas tank and loosening the gas cap helped get them going faster. Good luck mate

93 4X4 ext-cab, auto, SR5, 3.4 V6, supercharged, 2.1" pulley, URD fuel mods, Aquamist WI, IPT valve body mod, dual cases, 4" superlift, Alcan springs, 33 BFG MT, ARB locked front & rear, 5.29 US Gears, RB 1" BL, 1.5" BJ spacers, TJM T-17, Warn m8000.