i have a 1989 honda civic si with the stock d16a6 and i am getting a pulsating idle. it will idle at 1500 then drop to 800rpm then go back up to 1500 and drop again and repeat constantly. its really annoying. i replaced the IAC motor with one from an integra(will that work?) anyway it looked identical and fit perfect so i threw it in ....i am still getting the bad idle....is this a vacuum leak of some sort? anybody have this happen to them?

 

Your coolant level is probably low or needs to be purged. Sounds wierd but that causes a surging idle.

 

yeah i got this same damn problem!!! (except the engine sometimes shakes at higher speeds and then the check engine light comes on).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bejita &raquo;</TD></TR><TR><TD CLASS="quote">Your coolant level is probably low or needs to be purged. Sounds wierd but that causes a surging idle.</TD></TR></TABLE>

Do this if you're not getting a CEL, pretty common problem. I'd say it could still be a bad IACV but you've changed that. A vacuum leak would simply cause a high idle situation.

 

holy s*@$ it worked! how does something so simple make that big of a difference?