I failed to mention before that the speedometer stopped working after I put it back together. The VSS connector was solid, but no reading.
I put a multimeter on the VSS connector and turned on the car but got under 4 volts when it was supposed to read 8. Pushing the ECU wires around a little would get me 8v momentarily but it wouldn’t stick. I read that the VSS can run on 5V, so I ran a new ground wire to the MS central ground and tapped in to the 5V ref signal out of MS. Works like a champ.
Loose ECU wires does also explain the battery light that was coming on intermittently. Now I’m one step closer to just pulling the stock ECU out.