Strange Idles

hey all have just got a 4runner last month 1990 150k on it and this is what happened driving home from work the car started to smoke and stalled...after an hour it stopped smoking and i checked out the engine bay there was what looked like coolant everywhere...so i cleaned it got the radiator check out and everything was ok. now however when i start up the car it will idle incredibly high around 2-3k rpm and after a few minutes it starts to drop to normal then go up and keeps that cycle up...eventually stalling, now im wondering if maybe there is a problem with the radior or the vacum hoses throtle body anything like that? if anyone knows whats going on just send me a line i really like this truck and want to know what the issue is b4 i tackle fixing it :) thx