The IDLE contact [Supposed to be the Yellow/White wire] is the one which will have continuity with the CENTRE contact [White wire] when the TPS and butterfly are closed.
Use a test lamp or ohm meter to verify.
The third contact is for FULL throttle and the centre contact will have continuity to that when the TPS and butterfly are wide open.
That is normally wired to the Auto Trans ECU so if your engine came from a manual it may not be wired.
Don't know what his colour should be.
So at closed throttle, the centre pin will have continuity to one of the outside pins and not the other.
At full throttle, the centre pin will have continuity to the other outside pin.
In other words it is a changeover contact, the centre pin being the common.
Give it a whirl, you have a 50% chance of getting it right
I don't have the TPS, I'm using the FSM to help answer your Q.

cool thanks man but all u gave me was what 1 the centr is wat r uthe other 2 top n bottom??

According to the S13 FSM, the centre terminal is the Yellow wire, the IDLE contact is the Yellow/White wire.

hey anyone got a pic of there tps plug close up?? in my wiring someone cut plug off so today i cut 1 off a exa just wanna know wat colour goes where top middle n bottom on s13 silvia 180sx ca18 thanks guys