shuts off completely when I'm driving?

Hello,

This sounds like you have an issue with the crank position sensor.
With all the heat and vibration from the engine the crank sensor can lose its internal calibration. This can trigger the sensor to send incorrect data to the ECM. Then the ECM can shut down the engine. It can do that regardless of if the vehicle is moving or at stationary.
The crank sensor is located on the rear of the engine (see diagram below).

Here are few helpful articles:

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works
https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor
https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

I attached diagrams for your reference.

Please let me know of any questions.
Thank you.