[hotbug1776]

did you get a diagnostic done? the car starts and drives, but randomly shuts off. does it "choke" out like it loses power then stalls, or does it just shut off without any kind of warning? Have you done a fuel system flush? had the fuel pump pressure tested? only in the summer, hhmmmm. not the TPS, maybe the Idle air control, but that is useless at anything off idle, nevermind.

get the fuel system flushed/cleaned and tested for pressure. it's due anyway. then lets work on the ignition, perhaps a bad CPS (crank or cam) that fails when hot (thinking crank). the computer would lose the timing for the spark, and throw a CEL just before the motor died due to extreme timing loss.

work on the fuel system first though and eliminate the thing that are due for PM.

A lot of this was just thinking out loud (well, sorta) to help determine a possible solution, if nothing I mentioned works, then, the dealer knows best. and take the car to another dealer, just like a doctor, for a second opinion if need be (i know, more money).