All the comments I've seen on various forums about the throttle position sensor talk about a proble at constant 60mph+ cruising sppeds where the engin completely dies , but comes back to life as soon as pressure is even slightly released from the throttle. I've never had anyone say they've had the problem at low irregular speeds associated with off roading. Mine will stall if I try to drive too slowly through an obstical. I would look to your original problem and check/change all your HT leads and even the coil packs. Again with the throttle position problem I haven't heard of difficulty restarting the engin. Your description of a hot engin failing under load and being difficult to restart sounds very much like a coil/ht lead problem.