when i start up my 88 Honda accord LX it idles at about 1,500 rpms and after driving for about 5 minutes it goes up to about 2,500 rpm's but when i drive for about 30 minutes it goes down to .500 rpm's, is there a start up idle screw? or anything i can do about this problem

 

I'm not an expert on 88 Accords, but there should be a FITV, or fast idle thermo valve which makes the car idle higher until warm. Search for that and you'll find there are many threads that tell you how to adjust it back to spec. It's located on your throttle body and has coolant hoses coming and going from it...

 

'88 LX has a carburator, right? If so, there's no FITV. The fast-idle linkage is attached to the choke. You'll have to look at that linkage, & there's usually a cam that holds the throttle open a bit. Look for an adjustment there. Or at least clean up all that stuff if it's dirty/sticky.

 

im assuming the A20's dont have a warm up idle setting....of course that would probably only be in the PFI

 

agree with jim,, remove air cleaner, take a good look at all your linkages make sure none are bindind,, as for the idle dropping to 500 it is too low you might have to have all the setting adjusted if it is an automatic there is a sequence to adjust idle speeds ,,,,