where can you boost the idle of a 88 prelude with the air conditioning on? with the ac off it idles at about 1000rpm. when the ac is on it idles at a little over 500rpm. The car shakes alot when it has such a low rpm.

 

you might check your alternator, since it needs to handle the extra load when the AC is turned on. Also check the idle air control (IAC) valve and Fast Idle valve.

http://www.hondacarforum.com/h....html

 

Where is the IAC valve located? Thanks for responding.

 

I don't have the third gen manual here, or the model of your car. I know you can get a lot of 3rd gen information at the preludepower website.
you can also find the manuals for your model here http://media.honda.co.uk/car/o....html