I just bought a 95 Bonneville SSEi earlier this week as my new driver. The car ran perfect when I bought it, no issues at all. The other day i went to leave work and had the following problems:
Speedometer and the speed in the HUD are not working
High idle, around 500rpm higher then it should be.
Check engine light on
Traction Off light on and traction button does not work.

I had it on a scan tool today and it'* throwing all 3 QDM codes.
P1640: Boost control, EVAP purge and TCC solenoid
P1650: Shift and TCC solenoids
P1670: A/C relay and Fan relays

None of these seem to have anything to do with the speedometer or traction control. Im thinking maybe a bad ECM? Ideas?

the vss and a few of those things could use the same fuse and power wire i would start by investigating that

There is also ground busses under the floor. If those get corroded, which is known to happen, stuff doesn't ground. I would be inclined to check those. I believe they are just in front of the front doors, just under the carpet. There is for sure one on the drivers side, and I believe one on the passenger side as well.

fuse 5 has the o2, evap, boost control, egr, and some going to the trans, and ecm pin A15. according to my diagram it should be a pink wire

I will check more into the wiring. I looked over all of the relays and harnesses in the fuse/relay center under the hood. I need to check the harness going through the firewall to the ECM. Fuses are all good, checked all of them inside the car and under the hood.