Little boi

The other night I did a small pull and when I let off throttle I noticed the motor had turned off. The car had no power steering either but the dash and radio still had power. The car has only done this once before but I was able to turn it back on, this time the car only cranks.

Tested compression, fuel pressure, etc… all were good. The only thing that would make a difference is if we sprayed starter in the manifold and you can hear it try to start. We pulled the injectors keeping them attached to the rail and harness to see if they sprayed when starting the motor. They sprayed so fuel is fine but when we put the injectors and rail back we were checking the coils and plugs and noticed the spark plugs were dry. Obviously there’s an issue with either the engine harness or injector harness causing a short when the rail is in the right spot.

Is there any idea what would cause this to happen? My car has only shut off during the same circumstances. Only when I start hitting boost and let off, both times because I thought I saw a cop or suspicious headlights.