if you have an ek auto ex or dx 5 speed or manual it uses a 3 wire iacv that needs to be rewired if you are changing to 5 speed ek or any other besides the dx ek chasis and vice versa. if you don't convert to the appropriate iacv wiring/plug it'll idle like crap.

i can get you the info on the repinning. answer this first:
your chassis is a 99 ex auto right? what are you swapping to engine and ecu?