Problem after mpi conversion

[viper1431]

Hi, i've just helped a friend convert his EA falcon from cfi to mpi but have a slight problem with the car revving up and down a bit when you try and hold it steady. I did fix up the idle controller wires.
Thing is there seems to be a wire or two not right.
In the gregory's manual, looking at the wiring diagram it shows the three wires coming from the oxy sensor, two match the ones in his car but one is wrong. In his car one is grey with yellow stripe i think it was. Now i was trying to trace this back, i found the same color wire coming out of the TPS (was dark at the time so i may have gone off track but i think i was right)
Heres the problem... i followed that wire then up to the main large loom plug but on the ecu side of that plug it is just blanked off. We think this maybe causing the problem. Anyone know of the wire i'm talking about by any chance? Or come accross this same problem? The manual doesn't show that color wire anywhere but it's definately there and original and unfortunately can't find a different brand manual to see if the gregory's is just wrong.
Would appreciate any help.
cheers.

it could be your idle sensor, well most E-Series i've had the very rough idle so you could try replacin it with a new one, and if thats not the case then i cant help. good luck