Never heard of an "APPS", but what you are describing is a faulty CPS ( Crankshaft Position Sensor) plug connection, or the sensor itself. Had the same issue with my NA .
While driving along at 55, sudden loss of power, then resumes normally. While idling, stumbles, then recovers.
Replaced my CPS with a genuine Bosch, cleaned the connector harness with contact cleaner real good, and hasn't happened since.

I SERIOUSLY doubt the connector plate in the transmission has anything to do with it.

I think the "TB relay clip" you are referring to is the connector plug to the throttle body.
On the SRT6, the throttle body sits at the "Y" pipe. You can easily see the connector.