This reminded me of another crazy failure mode. The couplers to the IC pipes... I had an issue where the car all of a sudden sputtered, lost power but kinda seemed to be ok when on idle and no boost.. took me forever to find it but the passer side intercooler coupler ( Ic to Pipe) had a sort of “ flappy” tear in it.. on boost it would open up and vent then close back up when off boost.. was a factory style coupler, and was only 2 months old.. the tear was located underneath where it was totally impossible to see... I have since put the Lindsey silicone hoses on. No more issue..

 

If it turns out to be your speed or reference sensor, Pelican Parts has a great write-up.

https://www.pelicanparts.com/techart...eplacement.htm

I have just finished removing my damaged one. A few notes:

1. I did not need to remove the intake manifold
2. I sprayed PB blaster and let it soak over night.
3. I used a swivel attachment and a few socket extensions to reach the sensors.
4. I was able to pull out the sensor with my hand

The wires on the sensor were hard, dry and damaged.