Are you sure that is an electrical connector and not vacuum?
Include the wire stripe and colors, like blue/red. First color is the solid color and the second color is the stripe. Color photos don't work well, since each camera and computer reproduces colors differently.
Ok...more photos with color description. I forgot to add the the car was wired to run nitrous, but the PO removed the bottle (and I assume plate and solenoid since the intake is not plumbed) when he rebuilt the motor.
The first photo shows the 3 wires coming off the TPS (black, red green).
The second photo shows those 3 wires going into a connector.
The third photo shows where the white wire from the mystery connector was grafted into the either the red/green wire from the TPS.
The red wire to the mystery connector in the fourth photo (stay with me here) is spliced to a black wire that is bolted to the throttle cable plate which you can see in the second photo.
There is a lot of wire splicing and grafting on the car in general. The PO replaced the speedometer/tach section with all gauges, and he had to find an "old timer" to splice them all in and get them to work. I also see that the fuel injectors were spliced in...perhaps the 30lbs injectors had the wrong connecters...