crazy revving on mk2 16v

alrighty, my car has a running problem.my mechanic has found that a sensor that sits at the butterfly stop has had its plug cut off on the wiring loom side and he's no clue which way round they go into the sensor. One black wire, one black/yellow and one white. I haven't got any wiring diagrams for it and need it running better. Can anyone help?? cheers

I dont think it makes much difference which way round it goes as its only a switch to operate the isv. If thats the "sensor" you are on about.