when ever i wanna adjust the idle i just adjust the accel cable , where it connects there should be a spring , have no idea what its called but when the cars running you can push/pull it and the car will rev ... theres 2 nutz on the end of it .. i just loosen them and re-tighten them , moved of course .. then look at what the engine is idling at and adjust till you get it where you need ... please note , your supposed to be idling between 1.2-1.7 rpm ... you do not need to over do it .. if your car is having problems idiling and sputtering out this is NOT the fix , something is wrong and needs to be addressed. but if for say your not passing inspection due to where its at , then ya , thats a quick fix to get it past inspection ... here in TX ive had to do that once on a mazda ....
im not quite sure what ur 88 rx is supposed to be idiling at yet im sure one of these guys , or girls will be able to tell you that .. should also be in the book too ...
try looking for some pics of an 88 throttle body , or carb setup or an 88 assembled fuel rail .. once youve got pics we can edit them digitally and show you online what needs to be done ...
all else fails , take it to a qualified honda tech .