I have the fortune of having a 99 Honda Civic EX with the Idle issues P0505 Idle Air Control. After struggling with it for 3 days and throwing parts at the IAC code it turns out to be the injector seals which I am changing this week, so the moral of the story is nothing is a quick fix, just because you have a code doesn’t mean that’s the direct problem, in this case the code was a symptom so troubleshoot! Much thanks Eric for sharing your knowledge, you have been an incredible help!