First, find a new mechanic. The torque converter or its solenoid won't stop the car from starting.
My first guess is you have a cracked crank sensor. What I have seen over the years is that the sensor will start the engine and run until it gets hot. Once hot, the plastic on the sensor expands and the internal connection is lost. Thus, the engine dies.
Now, to properly check it, you would need a scanner to see if there is a crank signal to the ECM when the engine won't start. There are two other choices to check it. One, see if there is spark to the plugs when it won't start. If there IS, then there is a fuel delivery issue; a bad fuel pump could cause this. If there is no spark to ANY of the plugs, the crank sensor is my first suspect. If there is spark to some of the plugs and not others, the digital ignition control unit (DIC), which is what your coil packs mount to, is most likely the problem.
I hope this helps. If you are confused or need other help, let me know.
Friday, October 3rd, 2014 AT 10:47 AM