i have a 93 hatch with 99gsr, i believe its got an obd1 wiring harness, due to the fact that it has hondata s300, and no obdII port, i need to know which IAC to use, off a 94 ingegra gsr, or a 99 integra gsr, the only difference i see between the two are one one side of the ports on it has a lager diameter opening. The connectors seem to be the same i have a tune date monday and i have already smoked the intake and found no vacuum leaks, and my tb is a holley and i do not see any fast idle adjuster on it, i have an IAC on it that i do not know what it was off of but its def the wrong one, it idles at 2k rpms, and sometimes surges

 

it doesn't matter which one you use.

 

i couldnt tell u which IAC to use but just thought id throw out there that my car (92 civic with obd1 96gsr turbo) has already been tuned and i still have problems idling because i have no FIAC, no idle adjust screw because i have an aftermarket TB and im using 1000cc injectors. mine idles anywhere from 750 to 1400 but doesnt generally surge much if atall

 

The mounting hole pattern is different between OBD1 and 2, so if your motor is 99, you'll need the OBD2 IAC (96 & up) just so it'll bolt up. Most aftermarket IM should have provision for both both patterns.

A picture for you:

 

well i have the skunk 2 manifold, i believe it has both mounting holes for either, and the guys at T1 told me that with my idle randomly surging, then they will be unable to tune of of idle, but it only surges at times, it mainly stays around 2k until it warms up then it idles around 1200rpms after that