I'm new to the Z32 platform, my girlfriend and I recently picked up a '93 Z32 NA 2+2 and we're having an issue with an idle surge. When we first got it, it had a horrible misfire (caused by a dead fuel injector). I got that replaced and the car seemed to be much happier and the check engine light went away. But now it seems to have an idle surge. When you cold start the Z, it fast idles just fine, and then when it idles down it likes to slowly climb about 100 to 150 RPMS and hold it for about 5 seconds, then it drops down again and repeats. I've replaced pretty much all of the IACV hoses and vacuum hoses on the top/sides of the motor and it hasn't done much. Only thing I've noticed so far in my limited diagnostics, is when I unplug the IACV yellow plug the idle doesn't seem to change at all. I tested for continuity and voltage at the plug and it has both. So that's leading me to believe it's the physical IACV and not an electrical gremlin. Does anyone have any testing, other diagnostics I can try out, or any additional helpful information I might be missing?
Thanks a bunch!
