[CrazyHorst]

The crank position is the reference for the ignition.

Thinking abstractly here...the rotational position of the crank which informs the PCM about when TDC is approaching and thus when to fire the ignition...more complex than that as the PCM makes other "decisions" based on other inputs, but without the base reference pulse the ignition may not fire at all...and so...the engine stalls.

I would think there are two possible failure modes for the crank sensor, either it could go completely DOA or it could start going intermittent before it finally dies.

The mechanical fuel rail regulator is fairly low on the tree in terms of probability IMHO...I've never replaced one in all the miles driven below...

I mentioned the IAC port as the IAC motor can function perfectly, but it is actively metering a passage (I call this a "controlled leak") around the big throttle blade. Even though the motor works and responds properly, if the passage is carboned up it won't be able to control idle right...might be OK in neutral or park but get flaky when it has to compensate for the additional load of turning the torque converter when in Drive.