The PCM. I had the one from the buick in there thinking it would work fine but I had a 98 GTP bin file flashed to it due to VATS being on the buick and not on the GTP.
While I pissed around with this, that for months I ended up swapping the physical PCM with a different service number. Soon as I swapped it wha-fucking-la it worked.
Now most will say "why didn't you swap it out before"? I did when I first got the car running and it didn't change anything. Since January I got a new pre-made harness and apparently some of the wires were in the wrong spots. So some of it was the harness, and some was the PCM. Timing I guess.
It's pretty fun to drive. Got most of the cruising "tune" done. Just need to get the wideband installed and see if I'm already maxing my stock injectors or the tune is just super rich. I'm going with super rich at this point.