@lvec1 , Lou Vecchia, Possibly a stuck EGR valve or vacuum leak, although there are a lot of things that could cause idle problems, dirty carb., weak fuel pump, clogged filter, bad plugs, failing coil, etc. etc.. Links below may help trouble shoot your issue.
http://www.toyotanation.com/forum/80-89-95-toyota-pickup-hilux/43645-89-pickup-idles-rough-when-warm.html
http://4x4wire.com/forums/ubbthreads.php/topics/729973.html